Section 01-11: Glass, Frames and Mechanisms
1994 Mustang Workshop Manual
DIAGNOSIS AND TESTING

Pinpoint Tests

  

PINPOINT TEST A: POWER WINDOWS COMPLETELY INOPERATIVE

 

A1 CHECK SUPPLY AND GROUND

Yes
GO to A7.

No
GO to A2.

 

A2 CHECK GROUND CONTINUITY

Yes
GO to A3.

No
SERVICE open in Circuit 57 (BK). RESTORE vehicle. RETEST system.

 

A3 CHECK FOR SUPPLY VOLTAGE AT SWITCH

  • Measure for voltage between Circuit 400 (LB/BK) and a known good ground.
  • Is battery voltage present?
Yes
GO to A7.

No
GO to A4.

 

A4 CHECK SUPPLY CIRCUIT BREAKER

  • Gain access to fuse junction panel as outlined.
  • Using test lamp check for voltage to both sides of circuit breaker.
  • Is voltage present at both sides?
Yes
GO to A5.

No
REPLACE circuit breaker. RESTORE vehicle. RETEST system.

 

A5 CHECK SUPPLY CIRCUIT

  • Gain access to window regulator safety relay as outlined.
  • Disconnect window regulator safety relay and circuit breaker.
  • Using ohmmeter, check Circuit 194 (PK) for continuity.
  • Is resistance 5 ohms or less?
Yes
GO to A6.

No
SERVICE open in Circuit 194 (PK). RESTORE vehicle. RETEST system.

 

A6 CHECK WINDOW SAFETY RELAY GROUND

  • Using ohmmeter, check Circuit 57 (BK) at window regulator safety relay to a known good ground.
  • Is resistance 5 ohms or less?
Yes
REPLACE window regulator safety relay . RESTORE vehicle. RETEST system.

No
SERVICE open in Circuit 57 (BK). RESTORE vehicle. RETEST system.

 

A7 CHECK SWITCH CIRCUIT OPERATION

  • Using ohmmeter, check each window regulator electric drive circuit per charts below for continuity to ground.
  • Is there continuity on all circuits?
Yes
REPLACE window regulator control switch . RESTORE vehicle. RETEST system.

No
SERVICE suspect circuit for open. RESTORE vehicle. RETEST system.

  

PINPOINT TEST B: SINGLE POWER WINDOW INOPERATIVE

 

B1 DETERMINE INOPERATIVE WINDOW

  • Is passenger door window inoperative?
Yes
GO to B6.

No
GO to B2.

 

B2 CHECK INOPERATIVE WINDOW POWER SUPPLY

  • Remove left window regulator control switch per outline.
  • Using test lamp, connect lead to a known good ground.
  • Using chart below, connect test lamp to appropriate circuit.
  • Actuate window regulator control switch in appropriate direction and observe test lamp.

    Pin Circuit Circuit Function
    8 226 (W/BK) Left Front Window Down
    6 227 (Y) Left Front Window Up
    10 316 (Y/LB) Left Rear Window Down
    12 317 (GY/O) Left Rear Window Up
    11 319 (Y/BK) Right Rear Window Down
    13 320 (R/BK) Right Rear Window Up

  • Did test lamp illuminate?
Yes
GO to B3.

No
REPLACE window regulator control switch . RESTORE vehicle. RETEST system.

 

B3 CHECK INOPERATIVE WINDOW MOTOR CIRCUITS

  • Gain access to inoperative window regulator electric drive connector as outlined.
  • Disconnect window regulator electric drive connector.
  • Connect test lamp lead to a known good ground.
  • Using chart below, connect other end of test lamp to appropriate circuit.
  • Actuate window regulator control switch in proper direction and observe test lamp.

    Pin Circuit Circuit Function
    8 226 (W/BK) Left Front Window Down
    6 227 (Y) Left Front Window Up
    10 316 (Y/LB) Left Rear Window Down
    12 317 (GY/O) Left Rear Window Up
    11 319 (Y/BK) Right Rear Window Down
    13 320 (R/BK) Right Rear Window Up

  • Did test lamp illuminate?
Yes
GO to B5.

No
GO to B4.

 

B4 CHECK CIRCUIT CONTINUITY

  • Disconnect left window regulator control switch .
  • Using ohmmeter, check resistance of suspect circuit between harness connector and left window regulator control switch .
  • Is resistance 5 ohms or less?
Yes
GO to B5.

No
SERVICE open circuit. RESTORE vehicle. RETEST system.

 

B5 CHECK POWER WINDOW MOTOR

  • Using a jumper wire, connect one end to battery positive, connect other end to Pin 1 at window regulator electric drive.
  • With a second jumper wire, connect one end to a known good ground. Momentarily connect other end of jumper wire to Pin 2 of window regulator electric drive .
  • To reverse window regulator electric drive direction, switch jumper leads at window regulator electric drive .
  • Did window regulator electric drive operate correctly?
Yes
Power window OK. RESTORE vehicle. RETEST system.

No
REPLACE window regulator electric drive . RESTORE vehicle. RETEST system.

 

B6 CHECK INOPERATIVE PASSENGER DOOR WINDOW

  • Remove right window regulator control switch as outlined.
  • Using a test lamp, connect one end to a known good ground.
  • Connect other end to Circuit 313 (W/Y).
  • Actuate right window regulator control switch at left front door in the DOWN position. Observe test lamp.
  • Disconnect test lamp from Circuit 313 (W/Y), and connect test lamp to Circuit 314 (T/LB).
  • Actuate window regulator control switch in the UP position. Observe test lamp.
  • Did test lamp illuminate in either direction?
Yes
GO to B8.

No
If vehicle is a convertible, GO to B7 , sedan GO to B8.

 

B7 CHECK POWER WINDOW LOCK/UNLOCK SWITCH

  • Remove left window regulator control switch as outlined.
  • Actuate power window lock/unlock switch to the unlock position.
  • Using a voltmeter, test Circuit 170 (R/LB) for voltage to a known good ground.
  • Is voltage 10 volts or more?
Yes
GO to B8.

No
REPLACE left window regulator control switch . RESTORE vehicle. RETEST system.

 

B8 CHECK RIGHT POWER WINDOW DOWN CIRCUIT

  • Remove left window regulator control switch as outlined.
  • Connect test lamp to a known good ground.
  • Connect other end of test lamp to Circuit 313 (W/Y).
  • Actuate window regulator control switch in the DOWN position.
  • Did test lamp illuminate?
Yes
GO to B9.

No
REPLACE left window regulator control switch . RESTORE vehicle. RETEST system.

 

B9 CHECK RIGHT POWER WINDOW UP CIRCUIT

  • Disconnect test lamp from Circuit 313 (W/Y).
  • Connect test lamp to Circuit 314 (T/LB).
  • Actuate window regulator control switch in UP position.
  • Did test lamp illuminate?
Yes
GO to B10.

No
REPLACE left window regulator control switch . RESTORE vehicle. RETEST system.

 

B10 CHECK SUPPLY TO RIGHT POWER WINDOW SWITCH

  • Remove right window regulator control switch as outlined.
  • Connect voltmeter to Circuit 194 (P).
  • Is voltage 10 volts or more?
Yes
GO to B11.

No
SERVICE Circuit 194.

 

B11 CHECK RIGHT DOOR WINDOW MOTOR DOWN CIRCUIT

  • Using test lamp connected to a known good ground, connect other end to Circuit 333 (Y/R).
  • Actuate right window regulator control switch in the DOWN position. Observe test lamp.
  • Did test lamp illuminate?
Yes
GO to B12.

No
REPLACE right window regulator control switch . RESTORE vehicle. RETEST system.

 

B12 CHECK RIGHT DOOR WINDOW MOTOR UP CIRCUIT

  • Disconnect test lamp from Circuit 333 (Y/R). Connect test lamp to Circuit 334 (R/Y).
  • Actuate right window regulator control switch in the UP position. Observe test lamp.
  • Did test lamp illuminate?
Yes
GO to B13.

No
REPLACE right window regulator control switch . RESTORE vehicle. RETEST system.

 

B13 CHECK RIGHT DOOR WINDOW DOWN SUPPLY

  • Disconnect test lamp and right window regulator electric drive .
  • Connect test lamp to Circuit 333 (Y/R) at harness connector.
  • Actuate right window regulator control switch in the DOWN position.
  • Did test lamp illuminate?
Yes
GO to B14.

No
SERVICE open in Circuit 333 (Y/R). RESTORE vehicle. RETEST system.

 

B14 CHECK RIGHT DOOR WINDOW UP SUPPLY

  • Disconnect test lamp from Circuit 333 (Y/R).
  • Connect test lamp to Circuit 334 (R/Y) at harness connector.
  • Actuate right window regulator control switch in the UP position.
  • Did test lamp illuminate?
Yes
GO to B5.

No
SERVICE open in Circuit 334 (R/Y). RESTORE vehicle. RETEST system.

  

PINPOINT TEST C: ONE-TOUCH DOWN FEATURE INOPERATIVE

 

C1 CHECK SUPPLY TO ONE TOUCH MODULE

  • Gain access to module in left front door as outlined.
  • Turn ignition switch to RUN or ACC position.
  • Using voltmeter, connect one lead to Circuit 194 (P). Connect second lead to Circuit 57 (BK).
  • Did voltmeter show battery voltage?
Yes
GO to C3.

No
GO to C2.

 

C2 CHECK POWER WINDOW ONE TOUCH GROUND

  • Using ohmmeter, connect one lead to Circuit 57 (BK). Connect other lead to a known good ground.
  • Measure resistance.
  • Is resistance 5 ohms or less?
Yes
GO to C3.

No
SERVICE open in Circuit 57 (BK). RESTORE vehicle. RETEST system.

 

C3 CHECK ONE TOUCH DOWN SWITCH SENSE

  • Actuate driver's door window in the DOWN position. Hold button down.
  • Did window move down?
Yes
REPLACE one-touch module. RESTORE vehicle. RETEST system.

No
GO to Pinpoint Test B.

  

PINPOINT TEST D: WINDOW STUCK/BINDING

 

D1 WINDOW MOTOR RUNS SLOWLY

  • Remove trim panel at suspect window.
  • Actuate window in DOWN position.
  • Observe window in glass runs.
  • Is there obstruction in glass runs?
Yes
REMOVE obstruction. CLEAN and LUBRICATE glass run. RESTORE vehicle. RETEST system.

No
GO to D2.

 

D2 CHECK WINDOW REGULATOR OPERATION

  • Actuate window in UP position. Observe regulator operation.
  • Does regulator skip or bind?
Yes
GO to D3.

No
ADJUST regulator and guides as outlined. RESTORE vehicle. RETEST system.

 

D3 CHECK REGULATOR AND MOTOR

  • Remove window regulator electric drive as outlined.
  • Carefully inspect window regulator electric drive and regulator gears.
  • Is there damage to gears at regulator?
Yes
REPLACE window regulator as outlined. RESTORE vehicle. RETEST system.

No
REPLACE window regulator electric drive as outlined. RESTORE vehicle. RETEST system.

  

PINPOINT TEST E: REAR WINDOW WILL NOT DEFROST

 

E1 CHECK REAR WINDOW DEFROST SUPPLY

  • Remove heated back window switch and light as outlined.
  • Turn ignition switch to RUN position.
  • With test lamp connected to a known good ground, back-probe Circuit 298 (P/O).
  • Did test lamp illuminate?
Yes
GO to E2.

No
GO to E3.

 

E2 CHECK REAR WINDOW DEFROST GROUND

  • Using ohmmeter connected to known good ground, connect other lead to Circuit 57 (BK).
  • Measure resistance.
  • Is resistance 5 ohms or less?
Yes
GO to E3.

No
SERVICE open in Circuit 57 (BK). RESTORE vehicle. RETEST system.

 

E3 CHECK REAR WINDOW DEFROST SUPPLY CIRCUIT

  • Remove fuse 5 (15A) at fuse junction panel .
  • Using ohmmeter, check resistance between fuse output and Circuit 298 (P/O).
  • Is resistance 5 ohms or less?
Yes
GO to E4.

No
SERVICE open in Circuit 298 (P/O). RESTORE vehicle. RETEST system.

 

E4 CHECK REAR WINDOW DEFROST SUPPLY FOR SHORT

  • Using ohmmeter connected to known good ground, connect other lead to Circuit 298 (P/O). Read resistance.
  • Is resistance 5 ohms or less?
Yes
SERVICE short to ground Circuit 298 (P/O). REPLACE fuse 5 (15A). RESTORE vehicle. RETEST system.

No
REINSTALL fuse 5 (15A). GO to E5.

 

E5 CHECK GRID FEED TO DEFROST RELAY

  • Check output side of rear defrost fuse in power distribution box and harness with test lamp.
  • Did test lamp illuminate?
Yes
GO to E7.

No
GO to E6.

 

E6 CHECK GRID SUPPLY FOR SHORT TO GROUND

  • Using ohmmeter connected to known good ground, connect other lead to output side of rear defrost fuse (40A).
  • Is resistance 5 ohms or less?
Yes
SERVICE short to ground Circuit 175 (BK/Y). REPLACE rear defrost fuse (40A). RESTORE vehicle. RETEST system.

No
GO to E7.

 

E7 CHECK GRID SUPPLY FOR OPEN CIRCUIT

  • Using test lamp connected to known good ground, connect other end to Circuit 175 (BK/Y) at rear defrost relay.
  • Did test lamp illuminate?
Yes
GO to E8.

No
SERVICE open in Circuit 175 (BK/Y). RESTORE vehicle. RETEST system.

 

E8 CHECK RELAY OUTPUT TO GRID

  • With test lamp still connected to known good ground, connect other end to Circuit 186 (BR/LB).
  • Actuate ignition switch to ON position.
  • Did test lamp illuminate?
Yes
GO to E9.

No
REPLACE heated back window switch and light . RESTORE vehicle. RETEST system.

 

E9 CHECK REAR WINDOW DEFROST GRID FEED

  • Disconnect heated back window switch and light .
  • Disconnect feed wire at rear window.
  • Connect one lead of ohmmeter to known good ground; connect other lead to Circuit 186 (BR/LB).
  • Measure resistance.
  • Is resistance 5 ohms or less?
Yes
SERVICE Circuit 186 (BR/LB) for short to ground. RESTORE vehicle. RETEST system.

No
GO to E10.

 

E10 CHECK REAR WINDOW DEFROST GRID FEED FOR OPEN

  • Using ohmmeter, connect one lead to Circuit 186 (BR/LB) at heated back window switch and light . Connect other lead to window connector.
  • Measure resistance.
  • Is resistance 5 ohms or less?
Yes
GO to E11.

No
SERVICE open in Circuit 186 (BR/LB). RESTORE vehicle. RETEST system.

 

E11 CHECK GRID GROUND

  • Using ohmmeter, connect one lead to ground connector at grid.
  • Connect other lead to known good ground.
  • Measure resistance.
  • Is resistance 5 ohms or less?
Yes
System OK. RESTORE vehicle. RETEST system.

No
SERVICE open in Circuit 57 (BK) at rear window grid. RESTORE vehicle. RETEST system.