The body control module (BCM) monitors the rear fog lamp switch signal circuit in order to determine when the fog lamp relay is to be energized. When the BCM senses the rear fog lamp switch signal circuit low momentarily by pressing the rear fog lamp switch, the BCM energizes the fog lamp relay by grounding the rear fog lamp relay control circuit.
• | The battery voltage must be between 9.0-16.0 volts. |
• | Ignition switch in the RUN position. |
• | Rear fog lamp switch ON. |
When the rear fog lamp switch signal circuit is shorted to ground for approximately 3 minutes.
The rear fog lamps will not operate.
• | This DTC will clear on current status after the condition for setting the fault is corrected. |
• | A history DTC will clear after 100 consecutive ignition cycles without a fault present. |
• | History and current DTC(s) can be cleared using a scan tool. |
• | Test the rear fog lamp switch for sticking in the ON position. |
• | Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
The numbers below refer to the step numbers on the diagnostic table.
OFF is the normal state of the switch before activation.
OFF is the normal state of the switch before activation.
This step tests for a short to ground on the signal circuit.
After replacement of the BCM you must calibrate the new module for proper operation.
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
Schematic Reference: Fog Lights Schematics | ||||
1 | Did you perform the Lighting System Diagnostic System Check? | -- | Go to Step 2 | |
Does the scan tool display OFF? | OFF/ON | Go to Step 3 | Go to Step 4 | |
3 |
Does the rear fog lamp switch parameter change state? | -- | Go to Diagnostic Aids | Go to Step 4 |
Does the scan tool display OFF? | OFF/ON | Go to Step 7 | Go to Step 5 | |
Test the signal circuit of the rear fog lamp switch for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 | |
6 | Inspect for poor connections at the harness connector of the body control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 8 |
7 | Inspect for poor connections at the harness connector of the rear fog lamp switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 9 |
Did you complete the replacement? | -- | Go to Step 10 | -- | |
9 | Replace the rear fog lamp switch. Did you complete the replacement? | -- | Go to Step 10 | -- |
10 |
Does the DTC reset? | -- | Go to Step 2 | System OK |