• | 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. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Front Fog Lamp Switch Signal | 2 | 2 | 2 | -- |
Front Fog Lamp Relay Control | B2530 02 | B2530 05 | B2530 05 | -- |
Front Fog Lamp Control | 1 | 1 | 1 | -- |
Front Fog Lamp Relay Ground | -- | 1 | 1 | -- |
Fog Lamp - LF Ground | -- | 1 | 1 | -- |
Fog Lamp - RF Ground | -- | 1 | 1 | -- |
Fog Lamp Switch Ground | -- | 2 | 2 | -- |
1. Front Fog Lamps Malfunction 2. Front Fog Lamp Switch Malfunction |
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 battery voltage to the front fog lamp relay control circuit. When the front fog lamp relay is energized, battery voltage is applied via the FOG LAMP fuse to the front fog lamp supply voltage circuit which illuminates the front fog lamps. The BCM sends a serial data message to the instrument panel cluster (IPC) to enable the front fog lamp indicator.
Exterior Lighting Systems Description and Operation
Control Module References for scan tool information
Ignition ON, observe the scan tool Front Fog Lamp Switch parameter while pressing and releasing the front fog lamp switch. The reading should toggle between Active and Inactive.
⇒ | If the reading does not change between the commanded states, refer to Front Fog Lamp Switch Malfunction. |
⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance. |
⇒ | If not the specified value, test the signal circuit terminal 4 for a short to ground. If the circuit tests normal, replace the BCM. |
⇒ | If not the specified value, test the signal circuit terminal 4 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. |
⇒ | 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 C4 for a short to ground. If the circuit tests normal, test or replace the front fog lamp relay. |
⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
⇒ | 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. |
⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM. |
⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the BCM. |
Ignition ON, with a scan tool perform the display test for the IPC and observe the front fog lamp indicator.
⇒ | If the front fog lamp indicator illuminates during the test, replace the BCM. |
⇒ | If the front fog lamp indicator does not illuminate during the test or remains illuminated at all times, replace the IPC. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM or IPC replacement, setup, and programming |