Section 13-07: Clock
1994 Mustang Workshop Manual
DIAGNOSIS AND TESTING

Pinpoint Test

  

PINPOINT TEST A: CLOCK OPERATION ERRATIC OR INOPERATIVE

 

A1 CHECK SUPPLY FOR CLOCK MEMORY

Yes
GO to A2.

No
SERVICE Circuit 54 (LG/Y) for short to ground. RESTORE vehicle. RETEST system.

 

A2 CHECK MEMORY SUPPLY AT CLOCK

Yes
GO to A3.

No
SERVICE Circuit 54 (LG/Y) for open. RESTORE vehicle. RETEST system.

 

A3 CHECK IGNITION SUPPLY TO CLOCK

  • Using test lamp check Circuit 296 (W/P), Pin 2at clock connector for power.
  • Did test lamp illuminate?
Yes
GO to A5.

No
GO to A4.

 

A4 CHECK CIRCUIT 296 (W/P)

  • Using test lamp check output side of Fuse 6 (15A) for power.
  • Did test lamp illuminate?
Yes
SERVICE Circuit 296 (W/P) for open. RESTORE vehicle. RETEST system.

No
SERVICE Circuit 296 (W/P) for short. REPLACE Fuse 6 (15A). RESTORE vehicle. RETEST system.

 

A5 CHECK GROUND AT CLOCK

  • Using an ohmmeter connected to known good ground, connect second lead to Circuit 57 (BK), Pin 3 at clock connector.
  • Measure resistance.
  • Is resistance 5 ohms or less?
Yes
If illumination is the concern, GO to A6. If electric clock is inoperative, REPLACE electric clock . RESTORE vehicle. RETEST system.

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

 

A6 CHECK CLOCK DISPLAY

  • Turn headlamps to ON position.
  • Check clock display.
  • Did clock display dim?
Yes
GO to A8.

No
GO to A7.

 

A7 CHECK CIRCUIT 14 (BR)

  • Using test lamp check Circuit 14 (BR) for voltage.
  • Did test lamp illuminate?
Yes
GO to A8.

No
SERVICE Circuit 14 (BR) for open. RESTORE vehicle. RETEST system.

 

A8 CHECK CIRCUIT 19 (LB/R)

  • Using test lamp, check Circuit 19 (LB/R) for voltage.
  • Did test lamp illuminate?
Yes
GO to A9.

No
SERVICE Circuit 19 (LB/R) for open. RESTORE vehicle. RETEST system.

 

A9 CHECK CLOCK DIMMING OPERATION

  • Actuate headlamp switch dimming rheostat to FULL LOW and FULL HIGH position.
  • Observe clock illumination.
  • Did clock illumination go to FULL LOW and FULL HIGH illumination?
Yes
Clock is operational. VERIFY owners's complaint. RETEST system.

No
REPLACE electric clock . RESTORE vehicle. RETEST system.