Front Fog Lamps Malfunction
Front Fog Lamps Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
Diagnostic Fault Information
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 instrument panel module (IPM) 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 FOG LAMP fuse to the front fog lamp supply voltage circuit which illuminates the front fog lamps.
Reference Information
Schematic Reference
Fog Lights Schematics (Fog Lights Schematics)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Exterior Lighting Systems Description and Operation (Exterior Lighting Systems)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
1. Ignition ON, observe the scan tool Front Foglamp Relay Status parameter while activating the front fog lamp switch. The parameter should change between ON and OFF.
• If the parameter does not change between the commanded states, refer to Front Fog Lamp Switch Malfunction.
2. Turn the front fog lamps ON and OFF with the front fog lamps switch. The front fog lamps should turn ON and OFF as selected.
• If the front fog lamps do not change between the selected states, refer to Front Fog Lamps Malfunction.
3. Command the Display Test ON and OFF with a scan tool. The front fog lamps indicator should turn ON and OFF when changing between the commanded states.
• If the front fog lamps indicator illuminates during the test, replace the instrument panel module.
• If the front fog lamps indicator does not illuminate during the test or remains illuminated at all times, replace the instrument cluster.
Circuit/System Testing
Front Fog Lamp Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the turn signal/multifunction switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 3.
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp does not illuminate between B+ and the signal circuit terminal 4.
• If the test lamp illuminates, test the signal circuit for a short to ground. If the circuit tests normal, replace the IPM.
4. Install a 3 A fused jumper wire between the signal circuit terminal 4 and the ground circuit terminal 3. Verify the front fog lamps are illuminated.
• If the front fog lamps do not illuminate, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPM.
5. If all circuits test normal, test or replace the turn signal/multifunction switch.
Front Fog Lamps Malfunction
1. Ignition OFF, disconnect the front fog lamp relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal R4 and ground.
• If the test lamp illuminates, test the control circuit for a short to voltage.
3. Verify that a test lamp illuminates between the B+ circuit terminal R2 and ground.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal R3 for a short to ground. If the circuit tests normal, test or replace the front fog lamp relay.
4. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal R1 and ground.
• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.
5. Disconnect the harness connector at the inoperative front fog lamp.
6. Ignition OFF, scan tool OFF, exterior lamps OFF, test for less than 5 ohm between the ground circuit terminal 1 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect the harness connector at the inoperative front fog lamp.
8. Connect a 15 A fused jumper wire between the B+ circuit terminal R2 and the control circuit terminal R3. Verify the front fog lamps are activated.
• If the front fog lamps do not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the inoperative front fog lamp.
9. Connect a test lamp between the B+ circuit terminal R1 and the control circuit terminal R4
10. Command the Front Fog Lamps ON and OFF with the scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the IPM.
• If the test lamp is always OFF, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the IPM.
11. If all circuits test normal, test or replace the front fog lamp relay.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Front Fog Lamp Bulb Replacement (STS) (Service and Repair)
* Underhood Electrical Center or Junction Block Replacement (Removal and Replacement)
* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Turn Signal Multifunction Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for IPM or IPC replacement, setup, and programming