This handbrake switch is an electrical component that completes the parking-brake circuit when the lever is engaged. It mounts on the brake assembly and sends a signal to the instrument panel and the transmission control unit, which then locks the driveline. A failed switch prevents the parking-brake warning from illuminating and may allow the tractor to be driven with the brake partially applied. The switch uses two male pins for its connector and is threaded into the housing. On replacement, ensure the mating connector is clean and that the switch is seated fully before tightening.