anyone else have problems with thier 3rd high mounted brake light in the back glass? i have power all the way to the plug itself for the bulb. i did a continuity test with the bulb out and everytime i press the brake, it has power to the bulb, only the bulb won't light up....any ideas?

 

check the bulb itself if u havnt all ready or make sure its connected cleanly

 

mines doing the same thing...if its not one thing its another.

 

If you have power to the bulb, and the bulb is good, that only leaves the ground connection...

 

the contacts in the socket itself are pretty notorious for being the culprit. many times they will not make a good contact to the bulb. you can try to bend them inward somewhat, but you gotta be really careful cuz that stuff is very brittle and easy to break...

 

This reply might be a little late and simplistic, but when I had to change a couple of the bulbs in my 3rd brake light, I made the mistake of checking the function with the hatch up and the lights wouldn't work. When I closed the hatch, all bulbs had power.

 

It is a common mistake. The HMSL (High-Mount Stop Light) on 1987-90 F-bodies is powered through the contact pad on the hatch sill which makes contact with the spring-loaded contact pins when the hatch is closed. Clean the conact pad and pins with a scotch-brite pad.

Lon

 

The 91-92 cars don't power the brake light through those contacts. There is a stretchy cord at the top of the hatch that runs under the headliner.

 

I just removed the bulb and folded 2 narrow pieces of aluminum foil and folded one over each of the contacts. You have to fold it enough times that it's fairly thick, and then put the bulb back in. Solved the problem for me.

 

Bingo is correct in what he says about the ground. It is located under the headliner and uses the same ground as the map (dome) light.