Tests AD: The Daytime Running Lamps (DRL) Are Inoperative

PINPOINT TEST AD: THE DAYTIME RUNNING LAMPS (DRL) ARE INOPERATIVE

AD1-AD4:

AD4-AD7:

AD7-AD10:

AD10-AD12:

Normal Operation
The DRL relay 1 coil and input voltage is supplied by the central junction box (CJB) through circuit 295 (LB/PK) when the ignition switch is in the RUN position. The DRL relay 1 coil ground is provided by the parking brake switch through circuit 162 (LG/RD) when the parking brake is applied. When the DRL relay 1 is not energized (the parking brake is released), the DRL relay 1 routes voltage to the DRL relay 2 through circuit 175 (BK/YE). The DRL relay 2 then routes the voltage to the DRL relay 3 coil through circuit 1032 (WH/BK). The DRL relay 3 coil is grounded through circuit 57 (BK).

The DRL resistor receives voltage from the battery junction box (BJB) through circuit 554 (YE/BK). The voltage passes through the resistor to the DRL relay 3 through circuit 471 (OG/LG). When the DRL relay 3 is energized, the voltage is routed to the headlamps.

Possible Causes
- Fuse(s)
- Circuit 57 (BK) open
- Circuit 175 (BK/YE) open
- Circuit 295 (LB/PK) open
- Circuit 471 (OG/LG) open
- Circuit 554 (YE/BK) open
- Circuit 1032 (WH/BK) open
- DRL relay 1
- DRL relay 2
- DRL relay 3
- DRL resistor
- CJB