Battery voltage from the DRL Fuse 15 (C4/C5) or Circuit Breaker 15 (C6/C7/C8) located in the I/P-1 fuse block, is supplied at all times through the DRL Diode to the switch side of the DRL Relay. Battery voltage from the GAUGES Fuse 10 (C4/C5) or Circuit Breaker 10 (C6/C7/C8) also located in the I/P-1 fuse block is applied to the coil side of the DRL Relay with the ignition in the ON position. With the ignition in the ON position, battery voltage from the AUX WIRE Fuse 5 (C4/C5) or Circuit Breaker 5 (C6/C7/C8) located in the I/P-1 fuse block is applied to the DRL module. If the module senses that the park brake is not applied and the headlamps are OFF, it provides a path to ground to the coil side of the DRL relay energizing the relay. With the relay energized, battery from the DRL diode is applied through the switch side of the relay and the headlamp low beam supply voltage circuit illuminating the left and right low beam headlamps at a low intensity. If the DRL module senses that the park brake is applied or the headlamps are turned ON, it will cancel DRL operation.

Schematic Reference

Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, low beam headlamps ON, verify the low beam headlamps illuminate.

⇒	If the low beam headllamps do not illuminate, refer to Headlamps Malfunction.

2. Ignition ON, park brake OFF, verify the instrument panel cluster (IPC) park brake indicator is OFF.

⇒	If the park brake indicator is illuminated, refer to Brake Warning Indicator Malfunction.

3. Ignition ON, park brake OFF, headlights OFF, verify the DRL are illuminated and the IPC DRL indicator is ON.

⇒	If the DRLs do not illuminate, refer to Daytime Running Lamps Malfunction.

⇒	If the DRLs illuminate, but the DRL indicator does not illuminate, refer to Daytime Running Lamps Indicator Malfunction.

Daytime Running Lamps Malfunction

1. Ignition OFF, disconnect DRL relay.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal H86 and ground.

⇒	If the test lamp does not illuminate, test B+ circuit for a short to ground or an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal H87 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. Ignition OFF, connect the DRL relay and disconnect the harness connector at the DRL module.
5. Test for less than 5 ohms between the ground circuit terminal H and ground.

⇒	If greater than the specified range, test the ground circuit for a short to voltage or an open/high resistance.

6. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal C and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

7. Verify that a test lamp illuminates between the control circuit terminal G and ground.

⇒	If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit test normal, test or replace the DRL relay.

8. Connect 10A fused jumper wire between the control circuit terminal G and ground. The DRL should illuminate.

⇒	If the DRL do not illuminate, test the control circuit for a short to voltage. If the circuit tests normal, test or replace DRL relay.

9. If all circuits test normal, replace the DRL module.

Daytime Running Lamps Indicator Malfunction

1. Ignition OFF, disconnect the harness connector at the IPC.
2. Ignition ON, headlamps OFF, park brake OFF, verify that a test lamp illuminates between control circuit terminal B11 and B+.

⇒	If the test lamp does not illuminate, test the control circuit for a short to voltage or an open/high resistance.

3. If the circuit tests normal, replace the IPC.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.