Brake lights not working

I recently purchased a 1991 ext cab. The problem is that the brake lights do not work, but all others do. I checked fuses and even pulled the switch out from under the pedal and checked it with an ohm meter. Seemed to be in working order. Any and all advice would be appreciated. Thanks

Raynman: Welcome to the forum. When you say all the other lights work, are you saying the rear turn signals and the rear flashers are working? How about the 3rd brake light(if installed)? The circuitry for the left & right brake lights goes thru the turn signal switch and the 3rd brake light does not. Good job on checking the stop switch. That will eliminate it. Let us know........Steve

It does not have the third brake light option. Emergency flashers, turn signals, back up lights, and running lights all work

Sounds like the brake switch may not be adjusted right-if it is not adjusted right the brake lights will not come on-search this forum--there are good instructios on how to here.

The switch is fully extended when the pedal is depressed. I don't believe the switch to be my problem, as much as I think its electrical.

My'98 manual shows a "stoplight relay" in the underhood fuse block on pickups only. Not sure if your '91 has one. Otherwise you'll have to start checking for power into and out of the turn signal switch.

Try and pull your tail lights out, there is a circuit board that the lights plug into. Somtimes moisture gets in there and corrodes the board. But this may not be the case if it is just your brake lights that arn't working. Worth a try though i guess.

true, but if the brake lights don't work and the turn signals DO, I don't think it would be the board, as they are the same light bulb....check the switch for continuity and for 12V+, also check the stop lamp fuse, on a 91 I don't believe there is a stop lamp relay, but I may be mistaken.

I'd like to thank everybody for their help. It was only after I located a Chilton manual that I understood the whole turn signal switch thing. Turns out the wire for the brake lights had corroded and fallen out of the harness. Simple fix made easier by your help. Again, THANK YOU!:grinyes:

i had the same problem with my 94 sierra...it just turned out to be one of the break lights was burnt out...so check those...its worth a shot.