Went the other day to get the car inspected and the guy failed it b/c my 3rd breaklight doesn't work. I know its up to the inspector to pass or fail it and I guess I just took it to an *** that day. Well either way I looked at the wiring to the light and the rear defroster wire on the drivers side of the is missing( the little thin wire that runs along the top of the window). Now my question is how do I either replace that wire or just rewire the light. Are those wires pos or neg charged or what. I have a book but the setup looks kind of funny to me. Can any1 help with this?

I took the light off but it looks funny to me so I would rather have it on there. Also I have the external light.

Thanks in advance!

 

The missing ground strap for the defroster that your referring to has nothing to do with the third brake light. If this were the case, your defroster would constantly kick on the moment you apply the brakes. There should be a connector with two wire terminals (black and yellow) on the underside of the casing found on the glass of the hatch (assuming your third brake light is on the top of the hatch). If it's on the bottom of the hatch, it is found underneath the matching interior paneling under the hatch....

 

See you have the internal brake light but mines sits external. I'll post some pictures later on after i get home from work. When I disassembled the light I didn't see anywhere else the wires ran but to the wires for the rear defroster. I could be wrong though and the wires were cut and stuck somewhere.

 

I could only snap a quick picture of my '91 Formula's hatch for reference, as that's the only 3rd gen that I have left. However, any mid to late 80's F-Body, w/the 3rd brake light mounted externally (on the top of the hatch) should still be wired the same exact way though, with the wiring running forward along toward the dome light, then following it down toward the main harness....

 

Was very curious now, so I ran a quick search and found a response from a similar scenario by Trickster. If these 3rd brake light's (like your's) are in fact feeded through the defroster grounds, what an absolutely ridiculous configuration (with GM, I'm not surprised though), and I'm not surprised as to why they changed it later on. Gonna delve a little bit deeper into this myself, because now I'm very curious, but in the interim, Click Here, ....

 

Thanks man! When i did this search I came up with nothing.

 

I had a problem with my third brake light many years ago, and my memory is a little fuzzy. Yes I think that the rear defrost share a common ground, because if one of the wires get pulled off the struts when you hit your brake the rear defrost comes "on". The contacts next to the latch is where the brake gets it's power, but the problem that I had was that the contacts on the underside of the glass under the brake light wheren't making contact, so I had to take a strip of rubber(old bike innertube) under the lens so that the contacts stayed in contact.
I hope this helps, if not I can go home and take pictures of what I have when I get home.

 

If possible that would be nice. I forgot today was baby girls bday shes 4 so all car activities were put on hold till tomorrow. Thats just how the ball bounces. lol

 

this picture doesn't show it well but, (12 years ago) I took the light apart and under the the rubber strip I jammed a piece of rubber under to get the contact under to connect.


And this last picture shows how there are 2 wires on this side(1 on the other side) 1 for the defrost 1 for the light. (the other side is ground)

I hope this helps, tell me if you need more pictures, my car is easy to get pictures of.(collecting dust in the garage )

 

Yea I got what you're saying. When you look at the middle pic the wire from the top in the drivers side on my car leading from the light down is missing. So I'm thinking I can either rewire it to one of the breaklight wires or just find that wire and rerun it. Not sure but I will have to try and hit up a junkyard this weekend.
Thanks again!