Another Brake light problem... Which one of you wizards can help?

[Rustytuna]

I recently purchased a 91 fastback that wrecked into a deer. Well, I got the body fixed up and ready for inspection, but failed for a few simple things. The one issue that I never noticed was a brake light problem. My brake lights work normally when the headlight switch is off, but as soon as I turn it to the on position, the brake lights turn on. When i press on the brake pedal they slightly get brighter, but never fully turn off.

I checked the brake light sensor at the brake pedal and everything seems fine. The little plastic piece still gets pushed in by the brake, so I don't think its that. Also, this may not be part of the same issue, but the cluster lights and a/c lights don't work. The little led's on the cluster work, but none of the gauges light up.

P.S. The previous owner had some sketchy wiring done throughout the car. How sketchy you may ask? Well there were neons all over the car, under the dash, and even snake eyes. Also there is an aftermarket head unit, as well as an after market trigger switch that is on the center console that would control the neons. Well, if any of you guys could shed some knowledge my way, that would be greatly appreciated because at the moment, I am stumped. I disconnected most, if not all of the aftermarket wiring.

[brndck]

we won't be able to help much if the previous owner hacked up much of the stuff.
your best bet is to get a fsm or chilton manual, something with a complete wiring diagram of the system, and then bust out the voltmeter and go to town.

[Sumslapper]

we won't be able to help much if the previous owner hacked up much of the stuff.
your best bet is to get a fsm or chilton manual, something with a complete wiring diagram of the system, and then bust out the voltmeter and go to town.

yep you can get the whole fsm for your model online. Figure out what wires are the brake lights and trace them. The previous owner probably tapped into them somewhere. Check grounds too.

[Rustytuna]

Yeah, I looked into that, looks very complicated for someone without much electrical experience though. I will probably have a friend help me out with this one. I found out something interesting today though. If i take out my stop light fuse, my brake lights still work. Also, If i take out the one brake light, the brakelights work perfectly other than 1 bulb being out. Finally, when the light switch is off and i press the brakes, the little ding noise under the dash goes off and all my side markers and turn signal lights turn on.... Any clues?

[s14boy]

My brake lights work normally when the headlight switch is off, but as soon as I turn it to the on position, the brake lights turn on. When i press on the brake pedal they slightly get brighter

sounds like a troll to me!

[Ilya]

Do you actually have the right bulbs in? Teach bulb should have two filaments in it. One for lights and one for brakes.

[Rustytuna]

Do you actually have the right bulbs in? Teach bulb should have two filaments in it. One for lights and one for brakes.

I'll check the bulbs today.

[jr_ss]

Next time, please post this in the correct section. Gen Chat is not the Tech section the last time I checked.

As stated, you need to go through your chassis harness and find out what wires are spliced where and why. You may be better off finding a new harness and just replacing the current one.

[Rustytuna]

Do you actually have the right bulbs in? Teach bulb should have two filaments in it. One for lights and one for brakes.

That was it. The bulbs were a single filament, so I guess when i took out the stpo light fuse, it would stay on with the tail light circuit. Replaced the bulbs with 2 filaments inside and it works perfectly now! The only problem still is the interior back lighting for the a/c and cluster still don't work....