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 -
Written by Ken Lavacot Co-Founder and CEO of 2CarPros.com 35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.
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Article first published 2009-10-08 (Updated 2015-01-05)