Brake light

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2007 Volvo V70, 2006 Volvo V70, 2005 Volvo V70, 2004 Volvo V70, and 2003 Volvo V70. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying Rear Fog Lamp And Back-Up Lamp

Courtesy of VOLVO CARS OF NORTH AMERICA.

The stop lamps are in the tail lamps. The lamps light when the stop lamp switch on the brake pedal is closed. The stop lamp switch is connected to the central electronic module (CEM). The signal from the stop lamp switch is sent on to the rear electronic module (REM) via a hardwired cable. The power supply for the lamps is via a directly connected relay on the rear electronic module (REM). In order for the stop lamps to work when the ignition is not on, there is no logic in the rear electronic module (REM) to activate the relay. The relay is activated directly by the signal from the stop lamp switch. The rear electronic module (REM) receives data via the controller area network (CAN) from the central electronic module (CEM) indicating that the stop lamp switch is activated.

In order to detect faults in the stop lamps, the rear electronic module (REM) detects the power consumption in the lamp circuit using a directly connected shunt. If the power consumption falls below a certain limit, a fault is indicated and a text message is displayed in the driver information module.