Section 15-00: Audio Systems—Service
1994 Mustang Workshop Manual
DIAGNOSIS AND TESTING

Pinpoint Tests—Sound System Function

  

PINPOINT TEST A: RADIO CHASSIS INOPERATIVE/DOES NOT OPERATE PROPERLY

 

A1 VERIFY OPERATION OF RADIO CHASSIS

Yes
GO to A3.

No
GO to A2.

 

A2 VERIFY QUALITY SOUND FROM RADIO SPEAKERS

Yes
GO to Pinpoint Test B.

No
GO to A28.

 

A3 DISPLAY TEST-AM BAND INDICATOR

  • Press AM/FM button for AM band.
  • Press TUNE, SCAN or SCAN/TUNE button to station 1000 AM.
  • Is display correct and AM indicator lit?
Yes
GO to A4.

No
REMOVE radio chassis for service.

 

A4 DISPLAY TEST-FM1/FM2 BAND INDICATORS

  • Press AM/FM button FM1 band.
  • Press TUNE, SCAN or SCAN/TUNE button to station 88.9 FM.
  • Verify for FM2 band.
  • Is display correct and are FM1 and FM2 indicators lighting respectively?
Yes
GO to A5.

No
REMOVE radio chassis for service.

 

A5 DISPLAY TEST-ST STEREO INDICATOR

  • Press TUNE, SCAN, SEEK or SCAN/TUNE buttons to a local FM stereo station.
  • Is display correct and ST indicator lit?
Yes
GO to A6.

No
REMOVE radio chassis for service.

 

A6 SEEK-HIGHER FREQUENCY STATION

  • Press SEEK (>) and verify that number on display increases.

    NOTE: If display reads 1610AM or 107.9 FM, display will not increase. The SEEK (>) button should be pressed until display reads less than 1610AM or 107.9FM.

  • Is SEEK (>) operating properly?
Yes
GO to A7.

No
REMOVE radio chassis for service.

 

A7 SEEK-LOWER FREQUENCY STATION

  • Press SEEK (<) and verify that number on display decreases.

    NOTE: If display reads 530AM or 88.1FM, display will not decrease. The SEEK (<) button should be pressed until display reads greater than 530AM or 88.1FM.

  • Is SEEK (<) operating properly?
Yes
GO to A8.

No
REMOVE radio chassis for service.

 

A8 STATION RECALL MEMORY TEST

  • Press SCAN, TUNE, SEEK or SCAN/TUNE buttons to a desired station.
  • Press and hold one of the (1 through 6) memory buttons for two seconds until station sound is returned. (REPEAT for all six buttons)
  • Do for AM, FM1 and FM2 bands using 18 stations.
  • Turn radio chassis off, then on.
  • Press each station recall button and verify memory storage.
  • Is memory test successful?
Yes
GO to A9.

No
REMOVE radio chassis for service.

 

A9 VOLUME CONTROL TEST

  • Press VOLUME (+) and (-) to verify an increase and decrease in volume sound from radio chassis .
  • Does volume change properly?
Yes
GO to A10 if TUNE button equipped. Otherwise, go to A11 for SCAN or SCAN/TUNE.

No
CHECK radio speakers and connections. REFER to Symptom Chart if diagnosis finds inoperation in speakers. REPEAT volume test. If volume still inoperative, REMOVE radio chassis for service.

 

A10 TUNE CONTROL TEST (ESR)

  • Press TUNE button (>) or (<) to change the frequency station up or down one increment at a time. Change frequencies quickly by holding the (>) or (<) side of button. Verify for all bands.
  • Does TUNE operate properly?
Yes
GO to A12.

No
REMOVE radio chassis for service.

 

A11 SCAN MODE TEST (ESC OR PAC)

  • Press SCAN or SCAN/TUNE buttons to enter scan mode. (Go to PAC if ESC equipped).
  • Display will blink "SCN."
  • Press (>) side of SEEK button to begin forward scan mode up to next radio station for a five second sampling. Verify several stations.
  • Press (<) side of SEEK button to begin reverse scan mode. Verify several stations.
  • Stop scan mode by pressing SCAN/TUNE; or press the side of SEEK button presently matching direction of scanning.
  • Press SCAN/TUNE button twice to change radio stations up or down one increment of frequency at a time. (Display will read "TUNE"), then within five seconds press (>) or (<) side of SEEK button.

    NOTE: Change stations quickly by pressing and holding SEEK (>) or (<).

  • Scan mode will begin to scan up to next radio selection for a five second sampling.
  • Stop scan mode by pressing SCAN button.
  • Does scan mode operate properly?
Yes
GO to A12.

No
REMOVE radio chassis for service.

 

A12 TUNE ANTENNA TEST (OPTIONAL)

  • Tune radio on AM band outside of building.
  • Press SEEK to observe all listenable stations on band. Count number that can be tuned.
  • Compare to a vehicle with known good radio chassis.
  • Are normal number of stations received?
Yes
GO to A13 if AMS button equipped. If CLOCK button equipped GO to A14. Otherwise GO to A15.

No
If an absolute number of stations cannot be tuned, REFER to Section 15-02 to perform an Antenna System check. If antenna operative, REMOVE radio chassis for service.

 

A13 AMS-AUTOMATIC MUSIC SEARCH TEST-(ESC)

  • Press AMS button to change frequency up or down one increment at a time. After pushing AMS, press SEEK (>) or (<) and release to go in the direction desired. To change frequencies quickly, press SEEK (>) or (<) and hold.
  • Does AMS operate properly?
Yes
GO to A14.

No
REMOVE radio chassis for service.

 

A14 AUTO PRESET-AUTOMATIC MEMORY STORE (PAC)

  • Press AUTO PRESET button for three seconds.
  • Verify that radio chassis automatically presets six strong stations sequentially on memory recall buttons (1 through 6).
  • Turn off radio chassis , then turn back on.
  • Verify the same six stations are in memory for buttons (1 through 6).
  • Does AUTO PRESET operate properly?
Yes
GO to A15.

No
REMOVE radio chassis for service.

 

A15 TONE CONTROL TEST

  • BASS: Press AUDIO button repeatedly until "BASS" is displayed. Press VOLUME (+) to increase low frequency sounds and VOLUME (-) to decrease low frequency sounds.
  • TREBLE: Press AUDIO button repeatedly until "TREB" is displayed. Press VOLUME (+) to increase high frequency sounds and VOLUME (-) to decrease high frequency sounds.
  • Verify proper display and sounds for each tone control.
  • Do BASS and TREBLE operate properly?
Yes
GO to A16.

No
CHECK radio speakers and connections. REFER to Symptom Chart if diagnosis finds radio speakers inoperative. If tone bass and/or treble still inoperative, REMOVE radio chassis for service.

 

A16 BALANCE CONTROL TEST

  • BALANCE: Press AUDIO button repeatedly until "BAL" is displayed. Press VOLUME (+) to shift sound to right radio speakers and VOLUME (-) to shift sound to left radio speakers .
  • Verify proper display and sound in proper radio speakers .
  • Does BALANCE operate properly?
Yes
GO to A17.

No
CHECK radio speakers and connections. REFER to Symptom Chart if diagnosis finds radio speakers inoperative. If BALANCE still inoperative, REMOVE radio chassis for service.

 

A17 FADER CONTROL TEST

  • FADER: Press AUDIO button repeatedly until "FADE" is displayed. Press VOLUME (+) to shift sound to rear radio speakers and VOLUME (-) to shift sound to front radio speakers .
  • Verify proper display and sound in proper radio speakers .
  • Does FADER operate properly?
Yes
GO to A18 if tape player equipped. Otherwise, REFER to Symptom Chart to determine if an inoperative condition exists.

No
CHECK radio speakers and connections. REFER to Symptom Chart if diagnosis finds radio speakers inoperative. If FADER still inoperative, REMOVE radio chassis for service.

 

A18 TAPE PLAYER-LOADING TEST (ESC OR PAC)

  • With radio chassis POWER on and ignition switch in RUN or ACC insert known good cassette into tape player opening (with open edge of tape to the right). Verify automatic power loading (tape player draws tape in and begins playing tape).

    NOTE: If tape is at the end, playing will start on reverse side of tape.

  • Display will indicate arrows for (ESC) and whirling sprockets for (PAC) Stereo Systems.
  • Do loading of tape and display operate properly?
Yes
GO to A19 if (PAC) system. Otherwise, GO to A23.

No
REMOVE radio chassis with tape player chassis for service.

 

A19 TAPE PLAYER-SEEK TEST (PAC)

  • With tape playing, press SEEK (>) to go to the beginning of next tape selection. Press SEEK (<) to tune tape back to beginning of previous tape selection.
  • Does SEEK operate properly?
Yes
GO to A20.

No
REMOVE radio chassis for service.

 

A20 TAPE PLAYER-SCAN MODE TEST (PAC)

  • Press SCAN/TUNE button to enter scan mode (display will blink "SCN").
  • Press SEEK (>) to begin forward tape scan for a five second sampling of each selection.
  • Press SEEK (<) to begin reverse tape scan for a five second sampling of previous selection.
  • Stop scan mode by pressing the side of SEEK button matching the direction tape is currently scanning.
  • Does scan mode operate properly?
Yes
GO to A21.

No
REMOVE radio chassis for service.

 

A21 TAPE PLAYER-PLAY PROGRAM TEST (PAC)

  • Press and hold PLAY PROG button for one second to stop tape play and resume radio play. Press PLAY PROG again to stop radio play and return to tape play.
  • Does PLAY PROG operate properly?
Yes
GO to A22.

No
REMOVE radio chassis for service.

 

A22 TAPE PLAYER-REW/FF TEST (PAC)

  • Press REW button to rewind tape. The radio will automatically begin playing until rewind is manually stopped by pressing PLAY PROG button or tape is completely rewound.
  • Press FF button to fast-forward tape. Again, radio will begin playing until fast-forward is manually stopped by pressing PLAY PROG button or tape reaches end.
  • Does REW and FF operate properly?
Yes
GO to A25.

No
REMOVE radio chassis for service.

 

A23 TAPE PLAYER-AMS TEST (ESC)

  • Press AMS button. Push either left or right side of REV/ERSE button to find beginning of next selection in direction desired.
  • Does AMS operate properly?
Yes
GO to A24.

No
REMOVE radio chassis for service.

 

A24 TAPE PLAYER-REV/ERSE TEST (ESC)

  • Press the left side of REV/ERSE button to rewind tape playing forward. Return to tape play by pressing right side of button.
  • Press the right side of REV/ERSE button to fast-forward tape playing forward. Return to play by pressing left side of button.
  • Pressing both sides of REV/ERSE button simultaneously will reverse tape to opposite side (track) of tape.
  • Does REV/ERSE operate properly?
Yes
GO to A25.

No
REMOVE radio chassis for service.

 

A25 TAPE PLAYER-DOLBY TEST (ESC OR PAC)

  • Press memory button (3) to select Dolby® Noise Reduction. Verify quality of sound. (PAC)
  • Press Dolby® Noise Reduction button. Verify sound. Press to turn off.
  • Eject tape and verify Dolby® for Dynamic Noise Reduction on an FM stereo station. Verify sound. (ESC/PAC)
  • Does DOLBY operate properly?
Yes
GO to A26.

No
REMOVE radio chassis for service.

 

A26 TAPE PLAYER-EJECT TEST (ESC OR PAC)

  • Press EJECT or EJCT button to eject tape from opening. Radio chassis will resume playing if power on.

    NOTE: Tapes can be ejected with or without power on or ignition switch power.

  • Does EJECTING operate properly?
Yes
GO to A27.

No
REMOVE radio chassis for service.

 

A27 TAPE PLAYER-RADIO SPEAKER CONTROL TEST

  • Perform AUDIO button for BASS, TREBLE, BALANCE and FADER respectively, operating the VOLUME (+) and (-) for all conditions.
  • Perform just VOLUME in both conditions to verify sound loudness.
  • Do all speaker controls operate properly?
Yes
REFER to Symptom Chart to determine if an inoperative condition exists.

No
CHECK radio speakers and connections. REFER to Symptom Chart if diagnosis finds radio speakers inoperative. If radio speaker controls inoperative in radio chassis , REMOVE radio chassis for service.

 

A28 VERIFY INOPERATIVE OR INTERMITTENT

  • Verify if condition is intermittent or inoperative.
  • Is condition intermittent?
Yes
GO to A31.

No
GO to A29.

 

A29 CHECK FUSE

  • Turn ignition switch OFF.
  • Check fuse 11 and 8 in instrument panel fuse box. (PAC)
  • Check AUDIO fuse in engine fuse box.
  • Is either fuse open?
Yes
GO to A30.

No
GO to A31.

 

A30 CHECK FOR GROUNDED POWER FEED

  • With ignition switch OFF check fuse 11 Circuit 137(Y/BK) at radio chassis connector Pin 3 and fuse 8 Circuit 54(LG/Y) Pin 1 for a short to ground (PAC).
  • Is power feed grounded?
Yes
LOCATE short to ground and SERVICE or REPLACE as necessary. GO to A1.

No
REPLACE Fuse 11 or 8 and GO to A1. If fuse still opens, REMOVE radio chassis for service.

 

A31 CHECK POWER FEED

  • Connect voltmeter between radio chassis connector Pin 1 Circuit 54(LG/Y) or Pin 3 Circuit 137 (Y/BK) and known good ground.
  • Turn ignition switch to ON or ACC.
  • Does voltmeter indicate ten volts or more?
Yes
GO to A35.

No
GO to A32.

 

A32 CHECK WIRING CONTINUITY-FUSE

  • Check continuity between fuse 11 and radio chassis connector Pin 3 Circuit 137(Y/BK).
  • Check continuity between fuse 8 and Pin 1 Circuit 54(LG/Y) (PAC).
  • Does continuity exist?
Yes
GO to A33.

No
SERVICE wiring as required. GO to A1.

 

A33 CHECK WIRING CONTINUITY-IGN-FUSE

  • Check continuity between fuse 11 and ignition switch Circuit 297(BK/LG).
  • Check continuity between fuse 8 and engine compartment fuse box Circuit 38 (BK/O).
  • Does continuity exist?
Yes
GO to A34.

No
SERVICE wiring as required. GO to A1.

 

A34 CHECK IGNITION SWITCH POWER

  • Connect voltmeter between ignition switch connector Circuit 297 (BK/LG), 37 (Y) or 38 (BK/O).
  • Verify each circuit.
  • Turn ignition switch to ON or ACC.
  • Does voltmeter indicate ten volts or more?
Yes
REMOVE radio chassis for service.

No
SERVICE ignition switch .

 

A35 CHECK RADIO SPEAKERS

  • With radio chassis operating, check if condition is on all radio speakers .
  • Is condition present on all radio speakers ?
Yes
GO to A36.

No
GO to A37.

 

A36 CHECK RADIO ANTENNA

  • Check radio antenna and cable connections and wiring. (Refer to Section 15-02.)
  • Is antenna system operating properly?
Yes
GO to A37.

No
CONNECT, SERVICE OR REPLACE antenna components as required. GO to A1.

 

A37 CHECK RADIO CHASSIS

  • Substitute known good speaker to radio chassis .
  • Verify if condition is in radio speakers or radio chassis operation.
  • Is radio chassis operating?
Yes
CONNECT, SERVICE OR REPLACE radio speakers and wiring as required. GO to A1.

No
REMOVE radio chassis for service.

  

PINPOINT TEST B: RADIO CHASSIS DISPLAY BLANK--RADIO CHASSIS OPERATES

 

B1 VERIFY OPERATION OF RADIO CHASSIS

  • Turn ignition switch to ON or ACC.
  • Press radio chassis POWER on.
  • Is radio chassis display lit?
Yes
GO to Pinpoint Test A.

No
GO to B2.

 

B2 VERIFY QUALITY SOUND FROM RADIO SPEAKERS

  • Verify that quality sound is coming from radio speakers .
  • Is quality sound coming from radio speakers ?
Yes
GO to B3.

No
GO to Pinpoint Test A.

 

B3 CHECK WIRING CONNECTIONS-LCD WIRE

  • Check wiring connectors and wires for damage, corrosion or open wire at radio chassis connector Pin 4 Circuit 19 (LB/R).
  • Are wires and connections OK?
Yes
GO to B4.

No
SERVICE harness, connector and wiring as required. GO to B1.

 

B4 CHECK LCD SUPPLY

  • Connect voltmeter between radio chassis connector Pin 4 Circuit 19 (LB/R) and known good ground.
  • Turn ignition switch to ON or ACC.
  • Does voltmeter indicate ten volts or more?
Yes
REMOVE radio chassis for service. LCD display is internally inoperative.

No
GO to B5.

 

B5 CHECK FUSE

  • Turn ignition switch OFF.
  • Check fuse 13 in instrument panel fuse box.
  • Is fuse open?
Yes
GO to B6.

No
GO to B7.

 

B6 CHECK FOR GROUNDED ILLUMINATION FEED

  • Turn radio chassis OFF.
  • Check fuse Circuit 19 (LB/R) for continuity to known good ground.
  • Was illumination feed grounded?
Yes
LOCATE short to ground and SERVICE. REPLACE fuse 13. GO to B1.

No
REPLACE fuse 13. Operate. If fuse still opens, REMOVE radio chassis for service.

 

B7 CHECK WIRING—FUSE 13

  • Check continuity between fuse 13 and radio chassis connector Pin 4 Circuit 19 (LB/R).
  • Does continuity exist?
Yes
GO to B8.

No
REPLACE OR SERVICE wiring as required. GO to B1.

 

B8 CHECK WIRING—MAIN LIGHT SWITCH

  • Check continuity between fuse 13 and main light switch connector Circuit 19 (LB/R).
  • Does continuity exist?
Yes
GO to B9.

No
REPLACE OR SERVICE wiring as required. GO to B1.

 

B9 CHECK MAIN LIGHT POWER

  • Connect voltmeter between main light switch connector Circuit 19 (LB/R), and known good ground.
  • Actuate main light switch to full brightness.
  • Turn ignition switch to ON or ACC.
  • Does voltmeter indicate 10 volts or more?
Yes
REMOVE radio chassis for service.

No
GO to B10.

 

B10 CHECK CONTINUITY—MAIN LIGHT SWITCH

  • Check continuity between main light switch connector Circuit 195 (T/W) and main light switch connector Circuit 19 (LB/R).
  • Does continuity exist?
Yes
GO to B11.

No
SERVICE or REPLACE main light switch as required.

 

B11 CHECK FUSE 5

  • Turn ignition switch OFF.
  • Check fuse 5 in instrument panel fuse box.
  • Is fuse open?
Yes
GO to B12.

No
GO to B13.

 

B12 CHECK FOR GROUNDED ILLUMINATION FEED

  • Turn radio chassis OFF.
  • Check fuse Circuit 195 (T/W) for continuity to known good ground.
  • Was illumination feed grounded?
Yes
LOCATE short to ground and SERVICE. REPLACE fuse 5. GO to B1.

No
REPLACE fuse 5. OPERATE radio chassis . If fuse still opens, REMOVE radio chassis for service.

 

B13 CHECK CONTINUITY-CIRCUIT 38 (BK/O)

  • Check for continuity between I/P fuse 5 and engine compartment INT LPS fuse.
  • Does continuity exist?
Yes
CHECK engine compartment INT LPS fuse for open. REPLACE fuse if open, otherwise REMOVE radio chassis for service.

No
SERVICE Circuit 38 (BK/O) as required.

  

PINPOINT TEST C: RADIO CHASSIS/DIGITAL AUDIO COMPACT DISC PLAYER INOPERATIVE/DOES NOT OPERATE PROPERLY

 

C1 VERIFY OPERATION OF DIGITAL AUDIO COMPACT DISC PLAYER

  • Turn ignition switch to ON or ACC.
  • Press radio chassis POWER on.
  • Handling test disc by its edge (lable-side up), insert into digital audio compact disc player . Verify power loading.
  • Is digital audio compact disc player display lit?
Yes
GO to C3.

No
GO to C2.

 

C2 VERIFY QUALITY SOUND FROM RADIO SPEAKERS

  • Verify that quality sound is coming from radio speakers .
  • Is quality sound coming from radio speakers ?
Yes
GO to Pinpoint Test D.

No
GO to C11.

 

C3 DIGITAL AUDIO COMPACT DISC PLAYER-PLAY/STOP TEST

  • STOP: Press PLY/STOP button and verify disc stops playing, stop indicator (J) illuminates and operation returns to radio or tape mode.
  • PLAY: Press PLY/STOP button and verify disc resumes playing at point of stop, play indicator illuminates, track number illuminates and elapsed time illuminates.
  • Do play and stop operate properly?
Yes
GO to C4.

No
REMOVE digital audio compact disc player for service.

 

C4 DIGITAL AUDIO COMPACT DISC PLAYER-REVERSE/FAST-FORWARD TEST

  • Press REV/FF (>>) to fast-forward disc to a particular point.
  • Press REV/FF (<<) to reverse disc to a particular point.

    NOTE: Observe elapsed time to indicate where to stop.

  • Do reverse and fast forward operate?
Yes
GO to C5.

No
REMOVE digital audio compact disc player for service.

 

C5 DIGITAL AUDIO COMPACT DISC PLAYER-SCAN MODE TEST

  • Press SCAN button to activate scan mode.
  • Verify that disc scans to next selection and plays a five second audition, then advances to next until SCAN button is pressed again.
  • Verify display indicates track number and elapsed time.
  • Does scan mode operate properly?
Yes
GO to C6.

No
REMOVE digital audio compact disc player for service.

 

C6 DIGITAL AUDIO COMPACT DISC PLAYER-AMS CONTROL TEST

  • Press AMS (>>) to search for a later selection.
  • Press AMS (<<) to search for a previous selection.
  • Verify during play and stop modes.
  • Does AMS control operate properly?
Yes
GO to C7.

No
REMOVE digital audio compact disc player for service.

 

C7 DIGITAL AUDIO COMPACT DISC PLAYER-COMPRESS TEST

  • Press COMPRESS to bring the softer and louder passages together.
  • Verify display indicates "COMP."
  • Does COMPRESS operate properly?
Yes
GO to C8.

No
REMOVE digital audio compact disc player for service.

 

C8 DIGITAL AUDIO COMPACT DISC PLAYER-SHUFFLE TEST

  • Press SHUFFLE to allow digital audio compact disc player to randomly select and play music tracks.
  • Verify display indicates "SHUF."
  • Does SHUFFLE operate properly?
Yes
GO to C9.

No
REMOVE digital audio compact disc player for service.

 

C9 DIGITAL AUDIO COMPACT DISC PLAYER-EJECT TEST

  • Press EJECT button to eject disc and stop unit.
  • Verify display turns off and radio program or tape resumes playing.
  • Does EJECT operate properly?
Yes
GO to C10.

No
REMOVE digital audio compact disc player for service.

 

C10 DIGITAL AUDIO COMPACT DISC PLAYER-SPEAKER CONTROL TEST

  • With disc inserted, perform AUDIO button on radio chassis for bass, treble, balance and fader operating the Volume (+) and (-) for all conditions.
  • Perform just Volume in both conditions to verify sound loudness.
  • Do all radio speaker controls operate properly?
Yes
REFER to Symptom Chart to determine if an inoperative condition exists. Use appropriate diagnostic procedure.

No
GO to C11.

 

C11 CHECK CONNECTIONS BETWEEN UNITS

  • Check continuity of wiring between radio chassis connector and digital audio compact disc player connector.
  • Check connectors for damage, corrosion, open or shorted wires.
  • Are all wiring connections OK?
Yes
REMOVE digital audio compact disc player for service.

No
REPLACE OR SERVICE wiring as required. GO to C1.

  

PINPOINT TEST D: RADIO CHASSIS/DIGITAL AUDIO COMPACT DISC PLAYER DISPLAY BLANK-RADIO CHASSIS/DIGITAL AUDIO COMPACT DISC PLAYER OPERATES

 

D1 VERIFY OPERATION OF DIGITAL AUDIO COMPACT DISC PLAYER

  • Turn ignition switch to ON or ACC.
  • Press radio chassis POWER on.
  • Handling test disc by its edge (lable-side up), insert into digital audio compact disc player . Verify power loading.
  • Is Digital Audio Compact Disc Player display lit?
Yes
GO to Pinpoint Test C.

No
GO to D2.

 

D2 VERIFY QUALITY SOUND FROM SPEAKERS

  • Verify that quality sound is coming from radio speakers .
  • Is quality sound coming from radio speakers ?
Yes
GO to D3.

No
GO to Pinpoint Test C.

 

D3 CHECK WIRING CONNECTIONS—LCD WIRE

  • Check wiring connectors and wires for damage, corrosion or open wire at Digital Audio Compact Disc Player connector Pin 4 Circuit 19 (LB/R).
  • Are wires and connections OK?
Yes
GO to D4.

No
SERVICE harness, connector and wiring as required. GO to D1.

 

D4 CHECK LCD SUPPLY

  • Connect voltmeter between Digital Audio Compact Disc Player connector Pin 4 Circuit 19 (LB/R) and known good ground.
  • Does voltmeter indicate ten volts or more?
Yes
REMOVE digital audio compact disc player for service. LCD display is internally inoperative.

No
GO to D5.

 

D5 VERIFY RADIO CHASSIS DISPLAY

  • Verify that radio speaker display is lit with power on.
  • Is radio chassis display lit?
Yes
GO to D6.

No
GO to Pinpoint Test B.

 

D6 CHECK WIRING—FUSE 11

  • Check continuity between Circuit 19 (LB/R) splice and digital audio compact disc player connector Pin 4 Circuit 19 (LB/R).
  • Does continuity exist?
Yes
REMOVE digital audio compact disc player for service.

No
SERVICE wiring as required. GO to D1.

Sound Quality

  

PINPOINT TEST E: NOISY RECEPTION—AM AND FM

 

E1 CHECK ANTENNA CABLE CONNECTIONS

  • Verify condition by operating radio chassis while engine is running, with vehicle in or not in motion.
  • Check antenna cable connections including extension cable (if so equipped).
  • Are connections clean and secure?
Yes
GO to E2.

No
CLEAN and/or SECURE antenna cable connections as required.

 

E2 CHECK ANTENNA MOUNTING

  • Check to make sure antenna is securely mounted to body at ground points. (Electric antenna — mounting nut above fender; and also, make sure that prongs of grounding collar at fender underside are contacting metal.)
  • Are contacts clean and is there metal-to-metal contact?
Yes
GO to E3.

No
CLEAN and/or SECURE connections as required.

 

E3 CHECK SUPPRESSION EQUIPMENT

  • Check for presence of all required suppression equipment, radio frequency interference suppression bond and radio receiver hood bonding strap (if so equipped) for security, cleanliness and metal-to-metal connection.
  • Are connections OK?
Yes
GO to E4.

No
REPLACE missing equipment and/or CLEAN connections as required.

 

E4 CHECK MOUNTING AND CONNECTING WIRES OF FOLLOWING COMPONENTS

  • Check the mounting and connecting wires of the radio voltage regulator capacitor (if so equipped) and radio ignition interference capacitor for secureness, cleanliness and metal-to-metal contact. (Refer to Group 14).
  • Are connections OK?

    NOTE: The capacitor mounting points are used to complete the electrical circuit and must be mounted securely to clean surfaces.

Yes
GO to E5.

No
CLEAN and/or SECURE connections as required.

 

E5 CHECK OPERATION OF THE FOLLOWING COMPONENTS

  • Check the operation of the radio voltage regulator capacitor and radio ignition interference capacitor by replacing with known good components.
  • Check generator by disconnecting wiring harness from generator regulator .
  • Verify radio chassis reception.
  • Is noise eliminated?
Yes
SERVICE or REPLACE damaged components as required.

No
GO to E6.

 

E6 CHECK SPARK PLUG WIRES

  • Check spark plug wires for proper routing, grounding and secureness of connections.
  • Are wires OK?
Yes
GO to E7.

No
REROUTE or REPLACE spark plug wires or SECURE connections as required.

 

E7 CHECK IGNITION SYSTEM

  • Check ignition system for proper operation. (Use EEC-IV Intermittent Ignition Analyzer 007-00035 or check for open circuit spark plug wires using ohmmeter.) Also, check spark plugs for cracked insulators.
  • Is ignition system OK?
Yes
GO to E8.

No
SERVICE or REPLACE components as required.

 

E8 CHECK CHASSIS MOUNTING POINTS

  • Check all radio chassis mounting points for secureness, cleanliness and metal-to-metal contact.
  • Are mounting points OK?
Yes
GO to E9.

No
CLEAN and/or SECURE as required.

 

E9 SUBSTITUTE ANTENNA

  • Substitute a known good speaker and antenna being sure to ground antenna base to an unpainted metal surface.
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
REPLACE or SERVICE radio speaker or antenna.

No
GO to E10.

 

E10 SUBSTITUTE ANTENNA EXTENSION CABLE

  • Substitute a known good antenna cable.
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
REPLACE antenna extension cable.

No
GO to E11.

 

E11 SUBSTITUTE RADIO CHASSIS

  • Substitute known good radio.
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
Have radio chassis serviced at an authorized service center.

No
GO to E12.

 

E12 CHECK RADIO AMPLIFIER

  • Substitute a known good radio amplifier (ESC/PAC system only).
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
Have radio amplifier serviced at an authorized service center.

No
GO to E13.

 

E13 REPOSITION THE FOLLOWING COMPONENTS

  • Check if noise can be eliminated by repositioning antenna, radio speaker or radio power feed wires away from other wires and/or brackets.
  • Verify operation of radio chassis.
  • Is noise eliminated?
Yes
REPOSITION permanently by taping.

No
GROUND various parts of the vehicle to the frame using a jumper cable. For example, engine, fenders, quarter panels, stone deflectors, air cleaner, body sheet metal. When noise is eliminated, provide a permanent ground where required.

  

PINPOINT TEST F: NOISY RECEPTION—AM ONLY

 

F1 CHECK ANTENNA CABLE CONNECTIONS

  • Verify condition by operating radio chassis while engine is running, with vehicle in or not in motion.
  • Check antenna cable connections including extension cable (if so equipped).
  • Are connections clean and secure?
Yes
GO to F2.

No
CLEAN and/or SECURE antenna cable connections as required.

 

F2 CHECK ANTENNA MOUNTING

  • Check to make sure antenna is securely mounted to body at ground points. (Electric antenna — mounting nut above fender; and also, make sure that prongs of grounding collar at fender underside are contacting metal.)
  • Are contacts clean and have metal-to-metal contact?
Yes
GO to F3.

No
CLEAN and/or SECURE connections as required.

 

F3 CHECK SUPPRESSION EQUIPMENT

  • Check for presence of all required suppression equipment, radio frequency interference suppression bond and radio receiver hood bonding strap (if so equipped) for security, cleanliness and metal-to-metal connection.
  • Are connections OK?
Yes
GO to F4.

No
REPLACE missing equipment and/or CLEAN connections as required.

 

F4 CHECK MOUNTING AND CONNECTING WIRES OF FOLLOWING COMPONENTS

  • Check the mounting and connecting wires of the radio voltage regulator capacitor (if equipped) and radio ignition interference capacitor secureness, cleanliness and metal-to-metal contact. (Refer to Section 14-00).
  • Are connections OK?

    NOTE: The capacitor mounting points are used to complete the electrical circuit and must be mounted securely to clean surfaces.

Yes
GO to F5.

No
CLEAN and/or SECURE connections as required.

 

F5 CHECK OPERATION OF THE FOLLOWING COMPONENTS

  • Check the operation of the radio voltage regulator capacitor and radio ignition interference capacitor by replacing with known good components.
  • Check generator by disconnecting wiring harness from generator regulator .
  • Verify radio chassis reception.
  • Is noise eliminated?
Yes
SERVICE or REPLACE damaged components as required.

No
GO to F6.

 

F6 CHECK SPARK PLUG WIRES

  • Check spark plug wires for proper routing, grounding and secureness of connections.
  • Are wires OK?
Yes
GO to F7.

No
REROUTE or REPLACE spark plug wires or SECURE connections as required.

 

F7 CHECK IGNITION SYSTEM

  • Check ignition system for proper operation. (Use EEC-IV Intermittent Ignition Analyzer 007-00035 or check for open circuit spark plug wires using ohmmeter.) Also, check spark plugs for cracked insulators.
  • Is ignition system OK?
Yes
GO to F8.

No
SERVICE or REPLACE components as required.

 

F8 CHECK CHASSIS MOUNTING POINTS

  • Check all radio chassis mounting points for secureness, cleanliness and metal-to-metal contact.
  • Are mounting points OK?
Yes
GO to F9.

No
CLEAN and/or SECURE as required.

 

F9 SUBSTITUTE ANTENNA

  • Substitute a known good speaker and antenna being sure to ground antenna base to an unpainted metal surface.
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
REPLACE or SERVICE radio speaker or antenna.

No
GO to F10.

 

F10 SUBSTITUTE ANTENNA CABLE

  • Substitute a known good antenna cable.
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
REPLACE antenna extension cable.

No
GO to F11.

 

F11 SUBSTITUTE RADIO CHASSIS

  • Substitute known good radio.
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
Have radio chassis serviced at an authorized service center.

No
GO to F12.

 

F12 CHECK AMPLIFIER

  • Substitute a known good radio amplifier (ESC/PAC system only).
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
Have radio amplifier serviced at an authorized service center.

No
GO to F13.

 

F13 REPOSITION THE FOLLOWING COMPONENTS

  • Check if noise can be eliminated by repositioning antenna, radio speaker or radio power feed wires away from other wires and/or brackets.
  • Verify operation of radio chassis.
  • Is noise eliminated?
Yes
REPOSITION permanently by taping.

No
GROUND various parts of the vehicle to the frame using a jumper cable. For example, engine, fenders, quarter panels, stone deflectors, air cleaner, body sheet metal. When noise is eliminated, provide a permanent ground where required.

  

PINPOINT TEST G: NOISY RECEPTION—FM ONLY

 

G1 DETERMINE IF CONCERN IS WITH FM RECEPTION LIMITATION

  • Verify condition by operating radio chassis with engine running and vehicle not in motion.
  • If noise is on FM stereo, determine if customer concern is due to FM stereo reception limitation. Refer to normal operation description.
  • Is reception normal?
Yes
EXPLAIN and DEMONSTRATE to customer. INFORM customer of methods for obtaining best reception.

No
GO to G2.

 

G2 CHECK ANTENNA CABLE CONNECTIONS

  • Check antenna cable connections.
  • Are connections clean and tight?
Yes
GO to G3.

No
CLEAN and/or SECURE as required.

 

G3 CHECK ANTENNA MOUNTING

  • Check to make sure antenna is securely mounted to body and base screws are tight.
  • Are mounting points tight?
Yes
GO to G4.

No
SECURE as required.

 

G4 CHECK SPARK PLUG WIRES ROUTING

  • Check spark plug wires for proper routing and secureness of connections.
  • Are wires OK?
Yes
GO to G5.

No
REROUTE and/or SECURE connections as required.

 

G5 CHECK TYPE OF SPARK PLUG/WIRES

  • Check if wires are suppressor type and if spark plugs are the correct type.
  • Are wires and spark plugs correct?
Yes
GO to G6.

No
REPLACE spark plug or wires with the correct type.

 

G6 CHECK IGNITION SYSTEM

  • Check ignition system for proper operation. (Use EEC-IV Intermittent Ignition Analyzer (007-00035) or check for open circuit spark plug wires using ohmmeter.) Also, check spark plugs for cracked insulators.
  • Is ignition system OK?
Yes
GO to G7.

No
SERVICE or REPLACE components as required.

 

G7 CHECK CHASSIS MOUNTING

  • Check all radio chassis mounting points for secureness, cleanliness and metal-to-metal contact.
  • Are radio mounting points OK?
Yes
GO to G8.

No
CLEAN and/or SECURE as required.

 

G8 SUBSTITUTE ANTENNA

  • Substitute a known good antenna being sure to ground antenna base to an unpainted metal surface.

    NOTE: All surfaces used for grounding must be clean to ensure good electrical contact. Remove any dirt, rust, grease, paint, etc.

  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
REPLACE antenna.

No
GO to G9.

 

G9 SUBSTITUTE ANTENNA CABLE

  • Substitute a known good antenna cable.
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
REPLACE antenna extension cable.

No
GO to G10.

 

G10 CHECK GENERATOR

  • Check generator by disconnecting wiring from generator regulator .
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
CHECK generator . REFER to applicable Section in Group 14. SERVICE or REPLACE as required.

No
GO to G11.

 

G11 SUBSTITUTE RADIO CHASSIS

  • Substitute a known good radio chassis.
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
Have radio chassis serviced by an authorized service center.

No
GO to G12.

 

G12 CHECK AMPLIFIER

  • Substitute a known good radio amplifier (Premium system only).
  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
Have radio amplifier serviced at an authorized service center.

No
GO to G13.

 

G13 REPOSITION THE FOLLOWING COMPONENTS

  • Check if noise can be eliminated by repositioning antenna, speaker or radio power feed wires away from other wires and/or brackets.

    NOTE: All surfaces used for grounding must be clean to ensure good electrical contact. Remove any dirt, rust, grease, paint, etc.

  • Verify radio chassis operation.
  • Is noise eliminated?
Yes
REPOSITION permanently by taping.

No
GROUND various parts of the vehicle to the frame using a jumper cable for example, engine, fenders, quarter panels, stone deflectors, air cleaner, body sheet metal. When noise is eliminated, provide permanent ground where required.

  

PINPOINT TEST H: ONE OR MORE SPEAKERS DISTORTED—NOT ALL SPEAKERS

 

H1 CHECK FOR DISTORTION

  • Check all radio speakers for distortion.
  • Are all radio speakers distorted?
Yes
GO to Pinpoint Test I.

No
GO to H2.

 

H2 CHECK FOR RADIO SPEAKER PROBLEMS

  • Check for loose trim panels, grilles or attachments which might cause rattles in the area of the radio speaker which is considered distorted.
  • Check for pinched or broken wires at or near the radio chassis or radio speakers considered distorted.
  • Check for foreign material in radio speaker(s) cone.
  • Are there any visible radio speaker problems?
Yes
SERVICE as required. If still distorted, GO to H3.

No
GO to H3.

 

H3 CONNECT TEST SPEAKER

  • Connect a test radio speaker to the wiring for each distorted radio speaker .
  • Does the test radio speaker get distorted?
Yes
GO to H4.

No
REPLACE radio speaker as required.

 

H4 CHECK CONNECTIONS AND WIRING

  • Check for shorts between radio speaker connector.
  • Check radio chassis and radio amplifier , (if equipped) wiring harness for damage and shorts.
  • Are any shorts or damage found?
Yes
SERVICE as required.

No
GO to H5 if radio amplifier equipped. Otherwise, REMOVE radio chassis for service.

 

H5 CONNECT TEST AMPLIFIER

  • Connect a test radio amplifier in place of system radio amplifier .
  • Verify radio amplifier and radio chassis performance.
  • Does test radio amplifier cause distortion in radio speakers ?
Yes
REMOVE radio chassis for service.

No
REMOVE radio amplifier for service.

  

PINPOINT TEST I: ALL SPEAKERS DISTORTED

 

I1 CHECK FOR DISTORTION

  • Check all radio speakers for distortion.
  • Are all speakers distorted?
Yes
GO to I2.

No
GO to Pinpoint Test H.

 

I2 CHECK VOLUME RANGE FOR DISTORTION

  • Is distortion only at high volume?
Yes
System OK. STOP test.

No
GO to I3.

 

I3 CONNECT TEST RADIO CHASSIS

  • Connect a test radio chassis in place of system radio chassis .
  • Is distortion still present?
Yes
REMOVE radio amplifier for service.

No
REMOVE radio chassis for service.

  

PINPOINT TEST J: NO SOUND FROM ONE OR MORE SPEAKERS—NOT ALL SPEAKERS

 

J1 CHECK FOR SOUND AT EACH RADIO SPEAKER

  • Check for sound at each radio speaker .
  • Are all radio speakers without sound?
Yes
GO to Pinpoint Test K.

No
GO to J2.

 

J2 CHECK CONNECTORS TO RADIO SPEAKERS

  • Check wiring to inoperative radio speakers from radio chassis and radio amplifier for opens or shorts.
  • Are all connections and wiring OK?
Yes
GO to J3.

No
CONNECT, REPLACE or SERVICE as required.

 

J3 CHECK WITH TEST SPEAKER

  • Check system with test radio speaker substituted for system inoperative radio speaker .
  • Does test radio speaker operate?
Yes
REPLACE inoperative radio speaker .

No
GO to J4.

 

J4 CHECK RADIO CHASSIS AND RADIO AMPLIFIER WIRING

  • Check wiring between radio chassis and radio amplifier (if equipped) for damage, broken pins in connectors, solder bridges or stray wires that could cause shorts.
  • Are connections and wiring OK?
Yes
GO to J5.

No
CONNECT, REPLACE or SERVICE as required.

 

J5 CHECK WITH TEST RADIO

  • Substitute a test radio chassis for the system radio chassis .
  • Does test radio chassis provide sound to all radio speakers ?
Yes
REMOVE radio chassis for service.

No
REMOVE radio amplifier for service.

  

PINPOINT TEST K: NO SOUND FROM ALL SPEAKERS

 

K1 CHECK FOR SOUND AT EACH RADIO SPEAKER

  • Check for sound at each radio speaker .
  • Are all radio speakers without sound?
Yes
GO to K2.

No
GO to Pinpoint Test J.

 

K2 VERIFY POWER OF SYSTEM

  • Verify power ON and all radio speaker, radio chassis and radio amplifier connections and wiring are not damaged, loose, open or shorting.
  • With voltmeter verify power from radio chassis connector to ground.
  • If amplifier equipped, verify power from radio amplifier connector to ground.
  • Does voltmeter indicate ten or more volts?
Yes
GO to K4.

No
GO to K3.

 

K3 VERIFY CONTINUITY OF POWER CIRCUITS

  • Turn ignition switch OFF.
  • Using proper schematic for system inoperative, verify continuity of power circuits to source.
  • Verify voltage at ignition switch in ON or ACC.
  • Are the power circuits operating?
Yes
GO to K4.

No
SERVICE or REPLACE as required. RETEST for distortion.

 

K4 CHECK FOR SHORT TO GROUND AT SPEAKER(S)

  • Check for short to ground at one or more radio speakers which can cause radio amplifier shut-down.
  • Are any shorts found?
Yes
SERVICE as required.

No
REMOVE radio amplifier for service if equipped. Otherwise, REMOVE radio chassis for service.

  

PINPOINT TEST L: POOR SOUND QUALITY FROM ONE OR MORE SPEAKERS—NOT ALL SPEAKERS

 

L1 VERIFY POOR SOUND QUALITY IN RADIO SPEAKERS

  • Verify poor sound quality in radio speakers .
  • Is poor sound quality in all radio speakers ?
Yes
GO to Pinpoint Test M.

No
GO to L2.

 

L2 CHECK RESISTANCE OF RADIO SPEAKER(S)

  • With power off, check resistance of radio speakers that have poor quality sound from radio amplifier or radio chassis output, back to the return input on radio amplifier or radio chassis .
  • Is resistance load excessive of the 7 ohm speaker?
Yes
CHECK for load in radio speakers or wiring. Excess wire may cause loading effect. SERVICE and RETEST for quality sound.

No
GO to L3.

 

L3 CHECK RADIO SPEAKER(S)

  • Check radio speakers for damage to cone or a foreign material causing poor sound.
  • Verify radio speakers are securely mounted.
  • Are radio speaker (s) OK?
Yes
GO to L4.

No
SERVICE or REPLACE radio speaker and RETEST for quality sound.

 

L4 CHECK CONNECTIONS AND WIRING

  • Check connections and wiring at radio speakers , radio amplifier and radio chassis for damage, corrosion or shorts to grounds or loads.
  • Are connections and wiring OK?
Yes
GO to L5.

No
SERVICE or REPLACE connections and wiring as required. RETEST for quality sound.

 

L5 CHECK WITH TEST RADIO SPEAKER

  • Substitute a test speaker for system radio speakers that have poor quality sound.
  • Does test speaker have poor quality sound?
Yes
GO to L6 if separate radio amplifier equipped. Otherwise, REMOVE radio chassis for service.

No
REPLACE or SERVICE radio speakers as required. RETEST for quality sound.

 

L6 CHECK WITH TEST RADIO AMPLIFIER

  • Substitute a test radio amplifier for system amplifier.
  • Does test speaker have poor quality sound?
Yes
REMOVE system radio chassis for service.

No
REMOVE system radio amplifier for service.

  

PINPOINT TEST M: POOR SOUND QUALITY FROM ALL SPEAKERS

 

M1 VERIFY POOR SOUND QUALITY IN RADIO SPEAKERS

  • Verify poor sound quality in radio speakers .
  • Is poor sound quality in all radio speakers ?
Yes
GO to M2.

No
GO to Pinpoint Test L.

 

M2 CHECK CONNECTIONS AND WIRING

  • Check connection and wiring at radio speakers , radio amplifier and radio chassis for damage, corrosion or shorts to ground or loads.
  • Are connections and wiring OK?
Yes
GO to M3 if separate radio amplifier equipped. Otherwise, REMOVE radio chassis for service.

No
SERVICE or REPLACE connections and wiring as required. RETEST for quality sound.

 

M3 CHECK WITH TEST RADIO AMPLIFIER

  • Substitute a test radio amplifier for system radio amplifier .
  • Does test radio amplifier perform with poor quality sound?
Yes
REMOVE system radio chassis for service.

No
REMOVE system radio amplifier for service.