Fog Lamps Always On - Rear
WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Fog Lamps Always On - Rear
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Fog Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Body Control System Connector End Views in Body Control System. |
|||
| 1 | Did you perform the Lighting Systems Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Lighting Systems |
| 2 | Verify that the rear fog lamps are always on. Do the rear fog lamps operate normally? |
Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
| 3 | Use the scan tool to monitor the rear fog lamp switch input while depressing the switch several times. Does the scan tool indicate that the switch is ACTIVE at all times? |
Go to Step 4 | Go to Step 5 |
| 4 | Test for a short to ground in the rear fog lamp switch signal circuit. Did you find and correct the condition? |
Go to Step 13 | Go to Step 11 |
| 5 | Test the rear fog lamp relay control circuit for a short to ground. Did you find and correct the condition? |
Go to Step 13 | Go to Step 6 |
| 6 | Remove the rear fog lamp relay. Do the rear fog lamps turn OFF? |
Go to Step 7 | Go to Step 9 |
| 7 |
|
Go to Step 8 | Go to Step 12 |
| 8 | Inspect for poor connections at the harness connector of the Body Control Module (BCM). Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 13 | Go to Step 10 |
| 9 | Repair the short to voltage in the rear fog lamp supply voltage circuit. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
Go to Step 13 | - |
| 10 |
IMPORTANT:
Perform the setup procedure for the BCM. Replace the body control module (BCM). Refer to Body Control Module Replacement
in Body Control System.Did you complete the replacement? |
Go to Step 13 | - |
| 11 | Replace the rear fog lamp switch. Refer to Fog Lamp Switch Replacement - Rear . Did you complete the repair? |
Go to Step 13 | - |
| 12 | Replace the rear fog lamp relay. Refer to Relay Replacement (Within an Electrical Center)
or Relay Replacement (Attached to Wire Harness)
in Wiring Systems. Did you complete the repair? |
Go to Step 13 | - |
| 13 | Operate the system in order to verify the repair. Did you correct the condition? |
System OK | Go to Step 3 |