Normal Operation
WARNING: This page is about a different car, the 2007 Mercury Mariner and 2007 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The smart junction box (SJB) provides a reference signal to the fog lamp switch through circuit 1347 (DB/WH). When the fog lamp switch is engaged, the voltage signal is routed to ground through circuit 570 (BK/WH).
When the SJB detects the fog lamp switch has been pressed, the SJB provides a ground for the fog lamp relay coil through circuit 477 (LB/BK). When the fog lamp relay is energized, voltage is sent through circuit 478 (TN/OG) to the fog lamps. Voltage to the fog lamp relay is provided through circuit 554 (YE/BK).
Possible Causes
- Fuse
- Circuit 477 (LB/BK) open
- Circuit 478 (TN/OG) open
- Circuit 554 (YE/BK) open
- Circuit 570 (BK/WH) open
- Circuit 1347 (DB/WH) open, or short to ground
- Fog lamp relay
- Fog lamp switch
- SJB