Circuit Description
The fog lamp switch is a momentary switch and receives voltage on from the IGN 1 fuse in the instrument panel (I/P) fuse block. The body control module (BCM) monitors the switch on the front fog lamp switch signal circuit. When the switch is pressed voltage is supplied on the front fog lamp signal circuit only while the switch is held down.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B2743 Fog Lamp Switch Circuit High
Conditions for Running the DTC
| • | The ignition switch is in the RUN position. |
| • | The headlamp switch is in the headlamps ON or park lamps ON position. |
| • | The fog lamps are commanded ON. |
Conditions for Setting the DTC
Any of the following conditions will set this DTC:
| • | The front fog lamp signal circuit is shorted to voltage for 30 seconds. |
| • | The fog lamp switch sticks closed. |
Action Taken When the DTC Sets
DTC B2743 is stored in the BCM memory.
Conditions for Clearing the DTC
| • | The BCM receives the clear code command from the scan tool. |
| • | A current DTC will clear when the conditions for setting the DTC are no longer present. |
| • | A history DTC will clear after 100 malfunction cycles. |
Diagnostic Aids
If the DTC is a history DTC, the problem may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Fog Lights Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Do the fog lamps remain illuminated? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
3 | Disconnect the fog lamp relay. Did the fog lamps turn OFF? | Go to Step 4 | Go to Step 6 |
4 | Test the fog lamp relay control circuit 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 8 | Go to Step 5 |
5 | Inspect for poor connections at the fog lamp relay. 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 8 | Go to Step 7 |
6 | Repair a short to voltage in the front fog lamp supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 8 | -- |
7 | Replace the fog lamp relay. Refer to Relay Replacement in Wiring Systems. Did you complete the replacement? | Go to Step 8 | -- |
8 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3 |
