Diesel Data: Automotive Repair

Clock Display Circuit








OTHER SYSTEM: CLOCK: Clock Display Circuit

Clock Display Circuit

DESCRIPTION

The clock assembly uses this circuit to communicate with the main body ECU via the direct line. The main body ECU uses this circuit to send an auto dimmer signal to the clock assembly. The main body ECU detects the position of the light control switch according to the resistance. When the light control switch is set to the HEAD/TAIL position, the resistance between the HEAD/TAIL terminal and body ground is below 1 Ohms. When the light control switch is set to the HEAD/TAIL position, the main body ECU sends an auto dimmer signal to the clock assembly. When the clock assembly receives an auto dimmer signal from the main body ECU, the clock assembly causes the clock display to be dimmed.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (CLOCK ASSEMBLY - MAIN BODY ECU)




(a) Disconnect the E6 and F3 connectors.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
2. INSPECT MAIN BODY ECU
(a) Reconnect the E6 connector.




(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- GO TO LIGHTING SYSTEM
OK -- PROCEED TO NEXT INSPECTION PROCEDURE SHOWN IN PROBLEM SYMPTOMS TABLE