How to Find Brake Switch Wire in a 1978 Ford F-100 for Brake Controller Installation

Question:

I have a 1978 f-100 302 automatic Im having trouble with my brake switch wiring it seems to not have any voltage even when I connect my voltmeter to a chassis ground Ive already replaced the fuse also my blinkers and running lights work on both sides anyone had any of the similar problems

asked by: Justin C

Expert Reply:

Are your vehicle brake lights still working when you press the brake pedal? If so, then it sounds like maybe you are testing the wrong circuit.

It sounds like you could be installing a brake controller and are looking for the correct circuit to run to the stoplight circuit of the brake controller. If this is the case keep checking the circuits you found near the brake pedal till you find one that has 12 volts when the brakes are pressed and none when released.

For more information on brake controller installs check out the help article I attached.

expert reply by: Jameson C