Installing 3rd brake light on 85
Team Owner
Joined: Aug 2000
Posts: 40,156
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From: San Pedro CA
Pro
Joined: Apr 2003
Posts: 517
Likes: 0
From: South Lyon Michigan
Why would you want to put a third brake light on? I like the 85's specifically for the lack of the third brake light.
In any case are you installing one on the outside or on the inside of the rear window?
To wire it up all you need to do is connect it to one of the brake light wires that run to your rear lights, make sure its only the brake light wire as you only want it to come on when you hit the brake. If you don't want to wire it up that way you can run a wire to the brake switch right underneath your brake pedal. I don't recall the color of the wire which runs to the rear lights but if you do a simple test to see which wire gets power with a test light when you depress the brake you could figure it out.
Good luck.
In any case are you installing one on the outside or on the inside of the rear window?
To wire it up all you need to do is connect it to one of the brake light wires that run to your rear lights, make sure its only the brake light wire as you only want it to come on when you hit the brake. If you don't want to wire it up that way you can run a wire to the brake switch right underneath your brake pedal. I don't recall the color of the wire which runs to the rear lights but if you do a simple test to see which wire gets power with a test light when you depress the brake you could figure it out.
Good luck.
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,453
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From: crystalriver Florida
Well I tried that way (probing all the wires in the wire harness, but can't seem to find the juice, maybe I'll have to just use the wire under the brake pedal.....if anybody knows which color wire powers the brake lights ---PLEASE let me know, thanks
Team Owner
Joined: Dec 1999
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
The brake lamp switch on 86 and later cars has a separate circuit for the 3rd brake light and I think that wire is lt. blue. You should be able to use a circuit tester to see which wire goes the the brake lamps.
Melting Slicks
Joined: Jul 2003
Posts: 2,384
Likes: 124
From: Reno/Sparks Nevada
The only way to do this is to tap into the white brake light switch wire. There's an orange and a white wire at the switch. I picked this info from the Helms manual. I also have an '85 and did the same thing. If you try to use the brake light wiring at one of the tailights it'll light when you brake but when you use the turn signal it'll flash on the side you wired it to. The brake light and turn signal elements are the same, there is no separate wire in the rear of the car for a 3rd brake light.
Art
Art
Last edited by MrRenoman; Nov 22, 2004 at 09:17 PM.
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,453
Likes: 0
From: crystalriver Florida
Orange/ white wire, where is the switch that your referring to ? at the pedal or in the back inside the wire harness? And which wire do I tap into, the white wire or orange wire?
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Melting Slicks
Joined: Jul 2003
Posts: 2,384
Likes: 124
From: Reno/Sparks Nevada
Originally Posted by chillcat
Orange/ white wire, where is the switch that your referring to ? at the pedal or in the back inside the wire harness? And which wire do I tap into, the white wire or orange wire?
I promise!
Melting Slicks
Joined: Jul 2003
Posts: 2,384
Likes: 124
From: Reno/Sparks Nevada
I installed mine back in about '87 when it was a very popular thing to do. I don't regret it. I've got to admit stock '85s are truly unique in that they are distinguishable from any other '84-89 Vet. Although not as distructive as removing the split window of a '63, somehow it echoes the same kind of thought process. Modifying corvettes will never change. Now about that C4 to C5 conversion, now that's a ba$turd. 
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,453
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From: crystalriver Florida
Well, the reason I'm doing it, is because I have another strobe kit to wire inline with the 3rd light, so that when the brake is hit, the strobe sends 3-4 light strobes. For safety purposes, I would appreciate it if you could send me the wiring diagrams.....email is chillcat34433@yahoo.com
Team Owner
Joined: May 2002
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From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Originally Posted by chillcat
Well, the reason I'm doing it, is because I have another strobe kit to wire inline with the 3rd light, so that when the brake is hit, the strobe sends 3-4 light strobes. For safety purposes, I would appreciate it if you could send me the wiring diagrams.....email is chillcat34433@yahoo.com
Hey, that sounds pretty cool. I thought you were just tryin to look like an 86. I'll fire em off when i get home, send me an IM tomorrow if I forget.
Race Director
Joined: Feb 1999
Posts: 12,772
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From: Indianapolis IN
Originally Posted by jp2002ls1
Why would you want to put a third brake light on? I like the 85's specifically for the lack of the third brake light.
Good luck.
Good luck.
Same here, people have a 50/50 chance, if they "know Vettes", of figuring out if I have an 84 or 85,
until I turn the engine on, then they know something is up.
