B1024-14

B1024-14-REAR FOG LAMPS - CIRCUIT SHORT TO GROUND OR OPEN

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

Theory of Operation

The Body Control Module (BCM) receives the input from the Lower Switch Bank indicating that fog lamp illumination is requested. The BCM provides a ground path through the rear fog lamp relay control circuit. The rear fog lamp relay control circuit connects to the Rear Fog Lamp Relay, which when energized provides battery voltage to the Rear Fog Lamp. The Fog Lamp Relay is located in the Power Distribution Center. For additional information on the Rear Fog Lamp operation, Exterior Lamps - Operation.

- When Monitored:
With the ignition on.

Fog lamps off.

- Set Condition:
When the Body Control Module (BCM) detects a low condition on the (L239) Rear Fog Lamp Relay Control circuit.





1. CHECK FOR AN INTERMITTENT CONDITION
1. Turn the ignition on.
2. With the scan tool, clear all DTCs.
3. Turn the Fog Lamps off.
4. 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 REAR FOG LAMP RELAY
1. Turn the ignition off.
2. Remove the Rear Fog Lamp Relay and substitute it with a known good relay.
3. Turn the ignition on.
4. With the scan tool, read DTCs.

Does the scan tool display DTC: B1024-14-REAR FOG LAMPS - CIRCUIT SHORT TO GROUND OR OPEN?

Yes

- Go To 3

No

- Replace the Rear Fog Lamp Relay.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. CHECK THE (L239) REAR FOG LAMP RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Remove the Rear Fog Lamp Relay.
3. Disconnect the BCM C1 harness connector.
4. Measure the resistance between ground and the (L239) Rear Fog Lamp Relay Control circuit.

Is the resistance above 10k Ohms?

Yes

- Go To 4

No

- Repair the short to ground in the (L239) Rear Fog Lamp Relay Control circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. CHECK THE (L239) REAR FOG LAMP RELAY CONTROL CIRCUIT FOR AN OPEN
1. Measure the resistance of the (L239) Rear Fog Lamp Relay Control circuit between the Fog Lamps Relay and the BCM C1 harness connector.

Is the resistance below 5.0 Ohms?

Yes

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

No

- Repair the open in the (L239) Rear Fog Lamp Relay Control circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.