Circuit Description
The body control module (BCM) monitors the rear fog lamp switch signal circuit in order to determine when the rear fog lamp relay is to be energized. When the BCM senses that the rear fog lamp switch signal circuit is grounded momentarily by pressing the rear fog lamp switch, the BCM energizes the rear fog lamp relay by grounding the rear fog lamp relay control circuit.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2537 Rear Fog Lamps Circuit Low
Conditions for Running the DTC
The battery voltage must be between 9-16 volts.
Conditions for Setting the DTC
When the rear fog lamp switch signal circuit is shorted to ground for approximately 15 seconds.
Action Taken When the DTC Sets
The rear fog lamps will not operate.
Conditions for Clearing the MIL/DTC
| • | 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 DTCs can be cleared using a scan tool. |
Diagnostic Aids
| • | 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 . |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Fog Lights Schematics Connector End View Reference: Lighting Systems Connector End Views or Data Communication Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Does the scan tool display INACTIVE? | Go to Step 3 | Go to Step 4 |
3 |
Does the Rear Fog Lamp Switch Data parameter change state? | Go to Diagnostic Aids | Go to Step 4 |
4 |
Does the scan tool display INACTIVE? | Go to Step 7 | Go to Step 5 |
5 | Test the signal circuit of the rear fog lamp switch for a short to ground. Refer to Circuit Testing and Wiring Repairs . 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 BCM. Refer to Circuit Testing and Wiring Repairs . 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 Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 9 |
8 | Replace the BCM. Refer to Control Module References . Did you complete the replacement? | Go to Step 10 | -- |
9 | Replace the rear fog lamp switch. Refer to Rear Fog Lamp Switch Replacement . Did you complete the replacement? | Go to Step 10 | -- |
10 |
Does the DTC reset? | Go to Step 2 | System OK |
