Guys, I am putting the rear spoiler from an 86 to 90 that has the center brake light in the spoiler into my 92. I know that the cars that come with these spoilers have two metal pads that two "pins" come off the rear hatch to touch that makes the electrical contact to light the brake light. I believe these pads are inside the hatch seals which would make the contact pins have to be inside the hatch seals as well. How does this work?

In my 92, there is no way to run the wires from the light into inside the cabin. The spoiler doesn't go far enough forward and it's looking look I will have to run the brake light wires across the hatch seal to get inside the car. How does the factory wire the brake light wires from the light to the cabin. I already have the wiring run figured out from the car to the hatch. Any help will be greatly appreciated

 

The "pad" is on the plastic trim thats behind the taillights. Pos/neg are on that pad and spliced into the tail light harness. Only drawback to this set-up is the TBL only works when the decklid is closed. I never liked that method, so on my vert i ran the + wire inside the trunk, exit by the trunk hinge. Then down to behind the plastic trim to the TBL + wire that originally went all the way to the back of the car. The ground i simply grounded to the trunk structure.

When i added a TBL to my 84 i did the same, but exited the positive wire out the decklid where the hatch frame attaches to the decklid. I ran the wire under the frame, up to the top center. The drilled tiny hole for the wire, which i then routed to the driver side where the tail light harness is routed. Neg was grounded same as above.

You could re-route your harness from the top of the hatch in a similar way or just follow the stock routing, but you will need both male/female contact pads for the decklid/plastic trim. The mounting bracket for the decklid contact should already be on the decklid

 

@84 1LE im having issue with my TBL, which wire did you wire the power to. when i tried to wire to power my break TBL works but also blinks when turn signals are on.

 

On my 84 i believe the brake light wire is a lite blue color, but that's in a camaro. Can't say if it's the same on a firebird.
My 89, i think the TBL power is yellow, lite blue on the brk light, but again that's a camaro.

 

thanks ill check it out tomorrow to verify

 

I have the brake light power to the top of the cabin where the brake light sits at the top of the rear window so I'm pulling power from there. Since the hatch struts are electrically isolated and I don't have a rear window defroster, I'm running the power through them and then to the rear deck lid. I have got an upper contact plate coming from Hawks so hopefully that will get me across the rear hatch seal where I can go into the inner deck lid to the brake light wires. Time will tell if this plan works out.

 

hopefully it will work out for you

 

Well, it didn't work out so good. I have the contact plate from Hawks and the new spoiler light but there is some, as yet unseen by me, wiring in between them that bridges the gap and gets past the hatch seal. I can find nowhere on the hatch where there is an opening to put the wires through and the only way I can envision to get the wires through is to RTV them to the hatch so they don't catch on the seal. I'm sure Chevy didn't do this on thousands of cars for four years. I am missing something but am , obviously, clueless. Can someone with an IROC or something similar tell me how these two things connect PLEASE??

 

You should have two "plates" one for the decklid, one for the plastic trim behind the tail lights. Your car wont have any TBL wiring behind the plastic trim since your original TBL was up top on the glass. You have to re-route that wiring down to the area behind the taillights. That positive wire goes to one terminal on the contact pad on the plastic trim, neg goes to the other and to chassis ground. On the TBL you also have two terminals for pos/neg. So just match your polarities to that, continuity is made only when the hatch is closed.
Pics of what you have would help.

 

I believe I have made this sound much harder than it is. The ONLY place I'm having a problem is from the upper contact plate on the hatch to the brake light. Literally 6 inches of wire. I have power to the upper contact plate.
I can run the wire from the upper contact plate to the brake light but then I will have wires showing all the time and they will be pinched in the hatch seal when I close the hatch. The deck lid is made from two sheets of metal but the metal plates are tight together where the hatch seal is so there is nowhere to put the wires through to the light making it so the wires can't be run internally. I even bent up a long thin screwdriver and tried to push it through holes that are in between the plates to look for a small passage to run the wires. As far as I can tell, there is no small passage for the wires to pass through.

 

Your decklid doesn't have the hole for the wires to pass from under to the top, because your car never had a tbl on the spoiler. So you're going to have to drill a hole that will be hidden by the spoiler, but close enough to reach the tbl socket.

 

I don't think the spoiler goes far enough forward to get past where the hatch seal is on the underside. I'll look again but pretty sure (90%?)

 

Yep, there is barely enough room to get the hole into the interior but a small cross section does exist and my car is now wired. Sorry for being so dense about it. I sure like the looks of the brake light in the spoiler better than in the rear window, and the interior rear view mirror no longer has an obstruction from the brake light housing.