Braking Sensor/Switch: Description and Operation

DESCRIPTION
The switch travel of the brake light switch is designed so that the brake light lights up before braking pressure builds up. The switches are self-adjusting and are mounted in a bayonett lock in the pedal block through a 90� turn. By way of its self-adjustment function, the switch compensates for the tolerances in the pedals during initial assembly. However, if the switch is "overdressed" during work on the pedals or on the brake unit, the switch travel or pedal travel up to the switching point is lost.

The consequence: The brake lights are always on or flicker when travailing over bumps. In vehicles with cruise control, the cruise control can be deactivated as a result of vehicle vibrations under certain circumstances.

Therefore, the switches must be readjusted after any work in which the brake pedal is moved out of its "normal" position (for example, work on the pedals or on the brake unit).