Pinpoint Test 3: The Fog Lamps Are On Continuously

PINPOINT TEST 3: THE FOG LAMPS ARE ON CONTINUOUSLY

Normal Operation

The smart junction box (SJB) sends a reference signal to the headlight switch through circuit (BR) to monitor the fog lamp request. When the fog lamp switch is engaged, the voltage signal is routed to ground.When the SJB detects the fog lamps on request, the SJB provides ground to the fog lamp relay coil (integrated into the SJB). When the fog lamp relay is energized, voltage is routed through circuit (BR/Y) to the fog lamps and through circuit (BR/W) to the headlight switch for the fog lamps on indicator.

- DTC B2254 (Front Fog Lamp Switch Failure) - an on-demand DTC that sets when the SJB detects a short to ground from the fog lamp on input circuit.

Possible Causes
- Wiring, terminals or connectors
- Headlight switch
- SJB

Diagnostic Procedure

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