Pinpoint Test R: The Rear Fog Lamps Are On Continuously

Fog Lamps

Pinpoint Tests

Pinpoint Test R: The Rear Fog Lamps Are On Continuously

Refer to Wiring Diagram Set 86, Fog Lamps for schematic and connector information. Diagrams By Number

Normal Operation

When the headlamp switch is placed in the HEADLAMPS ON position and the fog lamp switch is engaged, the headlamp switch provides voltage to the rear fog lamps. Voltage is also routed to the Generic Electronic Module (GEM) to indicate the rear fog lamps are on (rear fog lamps on indicator).

- DTC B2509 (Rear Fog Lamp Switch Circuit Failure) - an on-demand DTC that sets when the GEM detects a short to voltage from the fog lamps voltage supply circuit.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Headlamp switch
- GEM



PINPOINT TEST R: THE REAR FOG LAMPS ARE ON CONTINUOUSLY

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

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R1 CHECK THE HEADLAMP SWITCH


- Ignition OFF.
- Disconnect: Headlamp Switch C205.
- Ignition ON.
- Do the rear fog lamps continue to illuminate?

Yes
GO to R2.

No
INSTALL a new headlamp switch. REFER to Headlamp Switch Service and Repair. CLEAR the DTCs. REPEAT the self-test.

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R2 CHECK THE GEM


- Ignition OFF.
- Disconnect: GEM C201b.
- Ignition ON.
- Do the rear fog lamps continue to illuminate?

Yes
REPAIR the rear fog lamps voltage supply circuit for a short to voltage. TEST the system for normal operation.

No
GO to R3.

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R3 CHECK FOR CORRECT GEM OPERATION


- Ignition OFF.
- Disconnect all the GEM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the GEM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?

Yes
INSTALL a new GEM. REFER to Body Control Systems. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR any DTCs. REPEAT the self-test.

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