Section 01-16: Wiper and Washer Systems
1994 Mustang Workshop Manual
DIAGNOSIS AND TESTING

Pinpoint Tests

  

PINPOINT TEST A: WINDSHIELD WASHER INOPERATIVE

 

A1 WINDSHIELD WASHERS INOPERATIVE

Yes
FILL windshield washer reservoir.

No
GO to A2.

 

A2 TURN ON WASHER SWITCH

Yes
GO to A3.

No
GO to A6.

 

A3 INSPECT NOZZLE FOR BLOCKAGE

  • Inspect windshield washer nozzle jet and bracket for blockage.
  • Are windshield washer nozzle jet and bracket blocked?
Yes
CLEAN or REPLACE windshield washer nozzle jet and bracket.

No
GO to A4.

 

A4 INSPECT HOSE, FILTER, CHECK VALVE FOR BLOCKAGE OR KINKS

  • Inspect hose for blockage or kinks.
  • Are any blockages or kinks present?
Yes
CLEAN, SERVICE or REPLACE as necessary.

No
GO to A5.

 

A5 INSPECT PUMP OUTLET FOR BLOCKAGE

  • Inspect washer pump outlet for blockage.
  • Is windshield washer pump outlet blocked or obstructed?
Yes
REMOVE washer pump from reservoir and clean. RETEST system.

No
REPLACE washer pump. RETEST system.

 

A6 CHECK FOR VOLTAGE AT WASHER PUMP

  • Using a voltmeter, actuate the turn signal and windshield wiper switch and check for voltage at windshield washer pump.
  • Is battery voltage present?
Yes
GO to A7.

No
GO to A8.

 

A7 CHECK PUMP GROUND

  • Check ground at pump connector.
  • Is connector properly grounded?
Yes
REPLACE windshield washer pump.

No
SERVICE ground.

 

A8 TURN ON WINDSHIELD WIPERS

  • Check operation of windshield wipers.
  • Do wipers operate?
Yes
GO to A9.

No
GO to Pinpoint Test B.

 

A9 CHECK WIPER SWITCH RESISTANCE AT WIPER CONTROL MODULE 

  • Unplug connector from wiper control module.
  • Depress windshield washer switch on end of turn signal and windshield wiper switch.
  • Check continuity between Circuits 993 (BR/W) and 590 (DB/W).
  • Is there continuity?
Yes
GO to A11.

No
GO to A10.

 

A10 CHECK WIPER SWITCH

  • Unplug wiper switch connector.
  • Depress turn signal and windshield wiper switch.
  • Check for continuity between terminals B and W.
  • Is there continuity?
Yes
SERVICE for open circuit between turn signal and windshield wiper switch and wiper control module.

No
SERVICE turn signal and windshield wiper switch.

 

A11 CHECK WASHER PUMP CIRCUIT

  • Check continuity of Circuit 941 (BK/W) from wiper control module to windshield washer pump.
  • Is there continuity?
Yes
REPLACE wiper control module.

No
SERVICE for open circuit.

  

PINPOINT TEST B: WINDSHIELD WIPERS INOPERATIVE—ALL CONTROL SWITCH POSITIONS

 

B1 CHECK FOR SUPPLY VOLTAGE AT MOTOR

  • Turn ignition switch to RUN.
  • Turn turn signal and windshield wiper switch to HI.
  • Unplug windshield wiper motor .
  • Check for battery voltage at Circuit 65 (DG).
  • Is battery voltage present?
Yes
GO to B2.

No
GO to B3.

 

B2 CHECK FOR BATTERY VOLTAGE AT THE WINDSHIELD WIPER CONTROL MODULE

  • Check for battery voltage at Circuit 65 (DG) Pin 2 of connector.
  • Is battery voltage present?
Yes
GO to B4.

No
SERVICE Circuit 65 (DG) for open circuit. RESTORE vehicle. RETEST system.

 

B3 CHECK CIRCUIT 65 (DB) SUPPLY

  • Using test lamp check for voltage at fuse 2 (30A).
  • Is voltage present at both sides of circuit breaker?
Yes
SERVICE Circuit 65 (DG) for open circuit. RESTORE vehicle. RETEST system.

No
REPLACE fuse.

 

B4 CHECK FOR BATTERY VOLTAGE TO MOTOR WINDINGS

  • Turn ignition switch to RUN.
  • Turn turn signal and windshield wiper switch to HI.
  • Disconnect connector from windshield wiper motor.
  • Check for battery voltage between Circuits 61 (Y/R) and 58 (W).
  • Is battery voltage present?
Yes
GO to B8.

No
GO to B5.

 

B5 CHECK FOR BATTERY VOLTAGE AT WINDSHIELD WIPER CONTROL MODULE CONNECTOR

  • Check for battery voltage between Pins 10 and 14 (Circuits 61 (Y/R) and 58(W) of windshield wiper control module connector with turn signal and windshield wiper switch in HI position.
  • Is battery voltage present?
Yes
SERVICE Circuit 61 (Y/R) or Circuit 58 (W) for open circuit. RESTORE vehicle. RETEST system.

No
GO to B6.

 

B6 CHECK WIRING BETWEEN WINDSHIELD WIPER CONTROL MODULE AND TURN SIGNAL AND WINDSHIELD WIPER SWITCH

  • Disconnect connector from windshield wiper control module.
  • Measure resistance between Circuits 993 (BR/W) and 589 (O) with turn signal and windshield wiper switch in HI position.
  • Is resistance less than one ohm?
Yes
REPLACE windshield wiper control module. RESTORE vehicle. RETEST system.

No
GO to B7.

 

B7 CHECK TURN SIGNAL AND WINDSHIELD WIPER SWITCH CONTINUITY

  • Disconnect harness from the turn signal and windshield wiper switch .
  • Check continuity between terminals for Circuits 993 (BR/W) and 589 (O) with turn signal and windshield wiper switch in the HI position.
  • Is resistance less than one ohm?
Yes
SERVICE Circuit 993 (BR/W) or Circuit 589 (O) for open circuit. RESTORE vehicle. RETEST system.

No
REPLACE turn signal and windshield wiper switch . RESTORE vehicle. RETEST system.

 

B8 WINDSHIELD WIPER MOTOR CURRENT DRAW TEST

  • Is current draw OK?
Yes
CHECK linkage as outlined. RESTORE vehicle. RETEST system.

No
REPLACE windshield wiper motor . RESTORE vehicle. RETEST system.

  

PINPOINT TEST C: WINDSHIELD WIPERS INOPERATIVE AT LOW SPEED

 

C1 CHECK FOR BATTERY VOLTAGE TO MOTOR WINDINGS

  • Turn ignition switch to RUN.
  • Turn turn signal and windshield wiper switch to LO.
  • Disconnect connector from windshield wiper motor.
  • Check for battery voltage between Circuits 61 (Y/R) and 56 (DB/O)
  • Is voltage present?
Yes
GO to C5.

No
GO to C2.

 

C2 CHECK FOR BATTERY VOLTAGE AT WINDSHIELD WIPER CONTROL MODULE CONNECTOR

  • Check for battery voltage between Pins 10 and 8 (Circuits 61 (Y/R) and 56 (DB/O)) of windshield wiper control module connector.
  • Is voltage present?
Yes
SERVICE Circuit 56 (DB/O) or Circuit 61 (Y/R) for open circuit. RESTORE vehicle. RETEST system.

No
GO to C3.

 

C3 CHECK WIRING BETWEEN WINDSHIELD WIPER CONTROL MODULE AND TURN SIGNAL AND WINDSHIELD WIPER SWITCH

  • Disconnect connector from with windshield wiper control module.
  • Measure resistance 4.between Circuit 993 (BR/W) and 589 (O) with turn signal and windshield wiper switch in LO position.
  • Is resistance between 3.5K and 4.5K ohms?
Yes
REPLACE windshield wiper control module. RESTORE vehicle. RETEST system.

No
GO to C4.

 

C4 CHECK CONTROL LINE SIGNAL AT TURN SIGNAL AND WINDSHIELD WIPER SWITCH

  • Disconnect harness from the turn signal and windshield wiper switch .
  • Check continuity between terminals for Circuits 993 (BR/W) and 589 (O) with turn signal and windshield wiper switch in LO position.
  • Is resistance between 3.5K and 4.5K ohms?
Yes
SERVICE Circuit 993 (BR/W) or Circuit 589(O) for open circuit. RESTORE vehicle. RETEST system.

No
REPLACE damaged turn signal and windshield wiper switch . RESTORE vehicle. RETEST system.

 

C5 WINDSHIELD WIPER MOTOR CURRENT DRAW TEST

  • Is current draw OK?
Yes
CHECK linkage as outlined. RESTORE vehicle. RETEST system.

No
REPLACE windshield wiper motor . RESTORE vehicle. RETEST system.

  

PINPOINT TEST D: WINDSHIELD WIPERS INOPERATIVE AT INTERVAL SETTING

 

D1 CHECK MODE SELECT INPUT SIGNAL

  • Disconnect connector from windshield wiper control module.
  • Measure resistance between Circuits 993 (BR/W) and 589 (O) with turn signal and windshield wiper switch at interval setting.
  • Is resistance between 10.5K and 12.0K ohms?
Yes
GO to D3.

No
GO to D2.

 

D2 CHECK MODE SELECT SIGNAL AT TURN SIGNAL AND WINDSHIELD WIPER SWITCH

  • Disconnect harness from the turn signal and windshield wiper switch .
  • Measure resistance between terminals for Circuits 993 (BR/W) and 589 (O) with turn signal and windshield wiper switch at interval setting.
  • Is resistance between 10.5K and 12.0K ohms?
Yes
SERVICE Circuit 993 (BR/W) or Circuit 589 (O) for open circuit. RESTORE vehicle. RETEST system.

No
REPLACE damaged turn signal and windshield wiper switch . RESTORE vehicle. RETEST system.

 

D3 CHECK INTERVAL SELECT INPUT SIGNAL

  • Rotate interval control on the turn signal and windshield wiper switch from MIN to MAX.
  • Measure resistance between Circuits 590 (DB/W) and 993 (BR/W).
  • Is resistance less than 104k ohms?
Yes
REPLACE windshield wiper control module. RESTORE vehicle. RETEST system.

No
GO to D4.

 

D4 CHECK INTERVAL SELECT INPUT SIGNAL AT TURN SIGNAL AND WINDSHIELD WIPER SWITCH

  • Disconnect harness from turn signal and windshield wiper switch .
  • Rotate interval control on the turn signal and windshield wiper switch from MIN to MAX.
  • Measure resistance between terminals of wiper switch for Circuits 590 (DB/W) and 993 (BR/W).
  • Is resistance less than 104K ohms?
Yes
SERVICE Circuit 590 (DB/W) or Circuit 993 (BR/W) for open circuit. RESTORE vehicle. RETEST system.

No
REPLACE damaged turn signal and windshield wiper switch . RESTORE vehicle. RETEST system.

  

PINPOINT TEST E: WINDSHIELD WIPERS WILL NOT PARK AT PROPER POSITION

 

E1 CHECK WIPER MOTOR GROUND

  • Unplug wiper motor connector. Check for ground at Circuit 57 (BK).
  • Is ground OK?
Yes
GO to E2.

No
SERVICE open circuit.

 

E2 CHECK FOR POWER AT WIPER MOTOR

  • Place ignition in RUN and turn signal/wiper switch at OFF.
  • Check for battery voltage between Circuit 65 (DG) and Circuit 57 (BK) at the motor connector.
  • Is battery voltage present?
Yes
GO to E3.

No
SERVICE open circuits.

 

E3 CHECK MOTOR CIRCUIT CONTINUITY THROUGH WIPER CONTROL MODULE

  • With wiper switch at OFF, check continuity of Circuit 28 (BK/PK) to 56 (DB/O) and Circuit 61 (Y/R) to 57 (BK).
  • Is continuity OK?
Yes
GO to E5.

No
GO to E4.

 

E4 CHECK CIRCUITS TO WIPER CONTROL MODULE

  • Check continuity of Circuits 28, 56, 61, and 57 from wiper motor to wiper control module.
  • Is continuity OK?
Yes
REPLACE wiper control module.

No
SERVICE open circuits.

 

E5 CHECK WIPER LINKAGE

  • Check that wiper linkage is not bent, cracked or mispositioned from motor shaft.
  • Is linkage OK?
Yes
REPLACE wiper motor.

No
SERVICE linkage.

  

PINPOINT TEST F: WINDSHIELD WIPERS CONTINUE TO RUN WHEN SWITCH IS TURNED OFF

 

F1 CHECK CONNECTIONS

  • Check that wiper motor and wiper control module connectors are fully seated.
  • Are connections OK?
Yes
GO to F2.

No
SERVICE as required. RECHECK system.

 

F2 CHECK CIRCUIT CONTINUITY THROUGH WIPER CONTROL MODULE

  • Disconnect windshield wiper motor.
  • With wiper switch at OFF, check continuity of Circuit 28 (BK/PK) to 56 (DB/O) and Circuit 61 (Y/R) to 57 (BK) at motor connector.
  • Is there continuity?
Yes
REPLACE wiper motor.

No
GO to F3.

 

F3 CHECK CIRCUITS TO WIPER CONTROL MODULE

  • Check continuity of Circuits 28, 56, 61 and 57 from wiper motor to wiper control module.
  • Is continuity OK?
Yes
GO to F4.

No
SERVICE circuits as required.

 

F4 CHECK CIRCUITS TO WINDSHIELD WIPER SWITCH

  • With wiper switch at OFF, measure resistance between Circuits 589 (O) and 993 (BR/W) at wiper module.
  • Is resistance 45k ohms to 50k ohms?
Yes
REPLACE wiper control module.

No
GO to F5.

 

F5 CHECK CIRCUIT CONTINUITY

  • Check continuity of Circuits 589 (O) and 993 (BR/W) between wiper switch and wiper control module.
  • Is continuity OK?
Yes
REPLACE wiper switch.

No
SERVICE open circuits.