Diesel Data: Automotive Repair

Test T

PINPOINT TEST T: THE EXTERIOR LAMPS ARE INOPERATIVE


Test T1:






Test T2:






Normal Operation
The instrument cluster monitors the headlamp switch position by sending out a voltage reference signal to the headlamp switch. When the headlamp switch is in the parking lamps ON position, the instrument cluster sends a signal to the front electronic module (FEM) and the rear electronic module (REM) to illuminate the parking lamps. If a problem is detected with the voltage reference signal to the headlamp switch, the instrument cluster will default the headlamps and parking lamps ON.

Possible Causes
- headlamp switch
- instrument cluster