B12A1-12

B12A1-12-LEFT DRL - CIRCUIT SHORT TO BATTERY

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

Vehicles with the Daytime Running Lamps (DRL) feature enabled illuminate the Park/DRL Lamp Bulbs in the upper cavity of the two front lamp units when the engine is running, the parking brake is released, the headlamps are turned OFF, and the optional automatic transmission gear selector lever is in any position except PARK. The park lamps may be ON or OFF for DRL to operate. For vehicles with a manual transmission, the DRL will operate in any transmission gear selector lever position. The BCM must be programmed appropriately for this feature to be enabled. For additional information on the DRL operation, Exterior Lamps - Operation.

- When Monitored:
With the DRL active.

- Set Condition:
When the Body Control Module (BCM) detects a short to voltage condition on the Left Daytime Running Lamp Driver circuit.





1. CHECK FOR AN ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
1. Turn the ignition on.
2. With the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

- Go To 2

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. CHECK THE (L58) LEFT DAYTIME RUNNING LAMP DRIVER CIRCUIT FOR A SHORT TO VOLTAGE IN THE HARNESS
1. Turn the Headlamps off.
2. Turn the ignition off.
3. Disconnect the Left Front Park/Turn Lamp harness connector.
4. Disconnect the BCM C1 harness connector.
5. Turn the ignition on.
6. Measure the voltage between ground and the (L58) Left Daytime Running Lamp Driver circuit.

Is there any voltage present?

Yes

- Repair the short to voltage in the (L58) Left Daytime Running Lamp Driver circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Go To 3

3. CHECK THE BCM FOR CORRECT OPERATION
1. Reconnect the BCM C1 harness connector.
2. Connect a 12-volt test light between the (L58) Left Daytime Running Lamp Driver circuit and (Z910) Ground circuit in the Left Front Park/Turn Lamp harness connector.
3. Turn the ignition on.
4. Turn the Headlamps on.

Does the test light illuminate brightly?

Yes

- Replace the Left Park/DRL Bulb. . Service and Repair
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Replace the Body Control Module (BCM). Body Control Module - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.