Fog Lamps

WARNING: This page is about a different car, the 2018 Ford Focus. However, it is still accessible from the selected car via links, so may be relevant.

The headlamp switch monitors the fog lamp switch and sends a headlamp switch status message over the LIN circuit to the BCM to indicate the fog lamp request.

When the BCM receives an input from the headlamp switch indicating a request for the fog lamps, the BCM provides ground to the fog lamp relay coil (integrated into the BCM). When the fog lamp relay is energized, voltage is routed to the fog lamps.

The BCM monitors the SASM for a high beam request through the LIN circuit. When the BCM receives a high beam request, the BCM will inhibit fog lamp operation. When the high beams are no longer requested, fog lamp operation is allowed.

The BCM also provides Field Effect Transistor (FET) protection of the fog lamp output circuits. When an excessive current draw is detected, the BCM disables the affected circuit driver.

Refer to: Module Controlled Functions - System Operation and Component Description .