BRAKE LIGHT SWITCH I've just purchased a 1993 GMC dually diesel 6.5 turbo diesel this weekend . We got it on the road and realized it had no brake lights so I had to follow my dad home. anyways we started to diagnose what the problem is this morning, the electrical on the truck is spaghetti and we're trying to locate where wires go and such, but we dont know where to look for the brake light switch. any help would be much appreciated. First truck and i went with the biggest i could find. Thanks again

There should be a switch mounted on the brake pedal. As you depress the brake pedal than the switch should activate. I would check the fuse box first and sure there is fuse installed for the brakes. If there isn't one then I would install one but be prepared for it to create other problems or to blow, because why would the previous owner remove it? If it blows then you have a short some place in the wires going to the brakes. I would also check the brake light bulbs and see if they are burned out or not. Is there a truck cap on the truck? I had a truck with a cap once and every time the wiring went funky on the cap it would cut the circuit to the brake lights.

Do your self a favor and get a Haynes manual from a local auto parts store. They are about $15-20. They will have wiring diagrams in the back and will allow you to trace wires. If you do not like that manual you can always try and order a Helm manual which is what dealer service departments typically use and probably more detailed.

appreciate the response, after some hunting underneath the dash we found that the previous owner had just removed the switch and had it hanging there, so hooked everything up and it all worked. appreciate the time.