Rear Fog Lamp

Fig 1: Identifying Rear Fog Lamps

Courtesy of VOLVO CARS CORPORATION

The rear fog lamp are in the tail lamps. The fog lamps are operated via a button in the light switch module (LSM). An LED in the button lights when the fog lamps are activated. The rear fog lamp can only be activated when low beam is on (market dependent). The light switch module (LSM) is directly connected to the central electronic module (CEM). The lamps are powered directly via an output on the central electronic module (CEM).

When reactivating key position II, the function is set to de-activated mode.

To detect faults in the rear fog lamps, the central electronic module (CEM) reads the power consumption of the circuit. If the power consumption falls below a certain limit, a fault is indicated and a text message is displayed in the driver information module.

There are diagnostics for the rear fog lamps.