Brake Light Switch

Article describes how an automotive brake light switch works.

When the brake pedal is depressed the brake light switch switch activates the brake lights. Many brake light switches have just 2 wires. When the brake pedal is depressed, a plunger contacts a plate completing the circuit within the switch. Brake light switches are also used as a cut off for the cruise control thus cutting off the cruise control to allow deceleration, or to trigger a shift lock control.

Brake Light Switch

On some vehicles the cruise control will have its own switch that is vacuum operated. The shift lock mechanism assures that the brake pedal is depressed before letting the vehicle be put into gear, avoiding accidental acceleration or rolling. Since the brake light switch is used many times, its a serviceable item and will eventually need to be replaced which is usually a simple procedure. These switches can usually be replaced with just a few basic tools. Always remember that with electrical devices such as brake light switches, OEM (original equipment manufacturer) part will work better and last longer.

If brake lights stop working. Visit - Brake light repair


Written by
Co-Founder and CEO of
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


Please use our question form if you have a specific question about your car as we are not able to give you a full answer on this page.

Article first published