Issue with brake lights and it’s not the bulb or fuse

Hello! Needing some help diagnosing my sons truck. He has no brake lights whatsoever. He has replaced the fuse and checked the bulbs, but still has no brake lights. Thinking it could be along the lines of a brake pedal switch (?), but want to make sure we are on the right track before we go replace it. Also, can anyone give suggestions on how to do this if it is the cause? This is a 1994 model…

Unplug the electrical connector from the brake light switch.

Plug a jumper wire into electrical connector.

If the brake lights come on, the brake light switch is the problem.

If the brake lights don’t come on, the problem is probably with the multi-function switch.



have you put a stick on the brake pedal and checked for power at the brake bulb sockets?

I don’t think he has. However, when he pulled one of the brake bulbs, the socket looked slightly “charred”.

If you know where the brake switch is, go look at it and see if it’s still in the right place so when your foot is off the pedal the switch button is pressed, and when you step on the pedal the switch button is released. These switches can go out of adjustment.

That sounds like the socket is corroded, which will easily cause this problem. Try cleaning the contacts on the socket, both where the bulb connects and where the wires on the back connect. May have to replace the housing.

Thanks everyone for the help! It was the brake switch. Trip to town and $9 later, he is good to roll.

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Congratulations on a job well done and sincere thanks for posting back. A happy ending is always good to hear, and few people take the time to post the results.