Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic approach.
- Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Front Fog Lamp Signal | 1 | 1 | 2 | -- |
Right Front Fog Lamp Ground | -- | 3 | -- | -- |
Headlight Switch 12 V Reference | 1 | 1 | 1 | -- |
Headlight Switch Signal | 1 | 1 | 2 | -- |
Left Front Fog Lamp Ground | -- | 4 | -- | -- |
1. Front fog lamps inoperative 2. Front fog lamps always ON 3. Right front fog lamp inoperative 4. Left front fog lamp inoperative | ||||
Circuit/System Description
The front fog lamp relay is supplied with battery voltage at all times. The front fog lamp switch signal circuit is grounded momentarily by pressing the front fog lamp switch. The body control module (BCM) energizes the front fog lamp relay by applying ground to the front fog lamp relay control circuit. When the front fog lamp relay is energized, the relay switch contacts close and battery voltage is applied through the front fog lamp fuse to the front fog lamp supply voltage circuit which illuminates the front fog lamps. With the front fog lamp switch activated the BCM sends a message via serial data to the instrument panel cluster (IPC) requesting the instrument panel cluster (IPC) to illuminate the front fog indicator.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
| • | Ignition ON, perform the Front Fog Lamps Relay Command test. The front fog lamps should be ON / OFF. |
| • | Ignition ON, perform the instrument cluster All Indicators test ON and OFF test. The front fog indicator should be ON / OFF. |
Circuit/System Testing
Front Fog Lamp Malfunction
- Ignition OFF, disconnect the appropriate harness connector at the front fog lamps listed below:
- Test for less than 5 Ω between the appropriate front fog lamp ground circuit harness connector terminal 2 and ground.
- Disconnect the KR46 Front Fog Lamp Relay.
- Ignition ON, test for less than 0.3 V between the signal circuit terminal 87 and ground.
- Ignition OFF, test for infinite resistance between the signal circuit terminal 87 ground.
- Test for less than 5 Ω between the signal circuit terminal 87 and the appropriate front fog lamp connector terminal 1.
- If all circuits test normal, replace the KR46 Front Fog Lamp Relay.
| • | E29LF Fog Lamp - Left Front |
| • | E29RF Fog Lamp - Right Front |
| ⇒ | If greater than the specified value, test the ground circuit for an open/high resistance. |
| ⇒ | If greater than the specified value, test the signal circuit for an short to voltage. |
| ⇒ | If less than the specified value, test the signal circuit for an short to ground. |
| ⇒ | If greater than the specified value, test the signal circuit for an open/high resistance. |
Front Fog Indicator Malfunction
- Ignition ON, command the instrument cluster All Indicators test ON and OFF with the scan tool. The front fog indicator lamp should be ON / OFF when changing between the commanded states.
| ⇒ | If the front fog indicator stays always on or always off, replace the P16 Instrument Panel Cluster (IPC). |
| ⇒ | If the front fog indicator is changing between ON and OFF, replace the K9 Body Control Module (BCM). |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM or instrument panel cluster replacement, setup and programming. |
