Brake Lamp Switch

DESCRIPTION
The plunger type brake lamp switch is mounted on a bracket attached to the brake pedal support.

CAUTION: The switch can only be adjusted during initial installation. If the switch is not adjusted properly a new switch must be installed.

OPERATION
The primary function of the switch is to turn on the brake lamps during braking. The switch is also used to send signals to components that must know when the brakes are applied, such as the Powertrain Control Module (PCM), which uses the signal to cancel speed control. The CAB uses the brake switch signal to monitor brake pedal application. When the switch contacts open (brakes applied), the CAB receives the brake applied signal. The CAB then monitors the RWAL system to anticipate the need for an RWAL stop.