Well, I searched but no luck on this one. 1st off, I thought my 3rd brake light did not work. The contacts next to the hatch pulldown I assumed were for the hatch (duh). Found out here, thats its for the 3rd brake light on mounted on the wing of my 90 firebird. So, I unscrewed it and found out it was not even connected! So connected it and as soon as I closed the hatch (car is not running btw) it lit up! Well, now it does not shut off. I started the car, pressed the brakes, shut it off, etc (maybe it would fix itself). But no, they are stuck "ON". So I had to disconnect it to save the battery.
Any ideas on how to fix it?? At least I know it actually works...

 

brake switch on the pedal assembly maybe?

 

Hmmm, dk, I checked that out and it "looks" ok. Funny, cause these 3rd brakes lights never work, but now it won't sutt off!

 

Brake switch on the pedal assembly is getting power, just checked. Is there any other way to tell if its bad? Strange...

 

mine hasnt worked since i got the car last year, took it to the dyno, and on the way out of the garage i noticed it on, they are real strange

 

This is strange. Im still amazed it actually works though. Now if I can just get it to turn off!

 

i am just curious, when your brake light is on, is the light for your defroster on as well? Because if it is, its a simple fix. The lead for yor defroster fell off. I dunno what wizard at GM dsigned the wiring for the 3rd brake light, but they included the defroser grid as well, and if the lead pops off then the defroster light comes on, and so does the brake light. If you manually shut off the defroster it will come back on as soon as you hit the brakes. The lead is located on the hatch strut. Its just a little stake-on. the wire will be right next to it. Go ahead and ask me how I know. Put it on, make sure its secure, all will be better.

 

-I don't have a rear defroster on mine. However everything else on the car works fine (electronicly). I'm still stumped

 

The black one is the 3rd brake switch assebly correct? It does not ine up w/the other one. I folded a piece of paper and jammed it in there so it would be flush, but that did not work, 3rd still stayed on. Should replace this right??

 

Take a multimeter, set it to measure resistance. Disconnect the brake switch from the wiring. Have one lead connected to one prong on the brake switch and the other lead connected to the other prong. If it reads something around 0 ohms, then its bad.

0 ohms means its shorted.

 

I will do that, man its going to be a pain getting in there and undoing the wires!

-but should it be "not flush" like that?

 

If the regular tail lights work properly, the problem is not likly in the switch.

I vote that you have a short in the hatch area.

Get a test light and test teh contacts with and with out the brakes depressed. Something is hot all the time that should not be.