trunk lid brake lights

[Bob Fouts]

OK this is the 85 with another question: The tail lights and brake lights in the rear fender work just fine. The tail lights in the trunk lid work but the brake lights don't. Th wiring harness for the trunk lid comes out of the left rear inner fender and doesn't seem to be directly connected to the harness for the fender lights. The wiring harness to the trunk lights consists of a white ground wire to each bulb, a black w green stripe (tail light) wire to each bulb, and a grey wire to the left bulb and a green wire to the right bulb. The grey and green wires which I assume are for the brakes don't have power when Judy hits the brakes. I suppose the quick and dirty solution is to run wire from the grey and green to one of the fender brake wires. Is there a better way or am I missing something? Appreciate any suggestions

Thanks Bob

[Gunslinger]

First and most obvious...did you check the bulbs to see if they don't have a burned out element in each? On my daily driver I had both brake lights out and didn't know until someone I know pointed it out to me. The turn signals worked...no brake lights.

The gray and green wires are probably used for both brake light and turn signals. Simply running a jumper wire may not do anything but make both trunk lights blink at the same time. I would guess if you ran a jumper wire you'd have to install a logic circuit to separate the brake and turn signal signal functions.

If the brake wires to the trunk lights don't have power when the brakes are applied (I assume you've used a test light to verify that), then you have to trace those wires down to their source to see if they're getting power from there. There could be a ground problem for those lights or a broken wire. There could even be an inline fuse that's blown.

[Mel]

Not sure why you're not getting power to the (trunk lid) brake lights but don't run just one wire from one of the fender brake lights to both trunk lid lights. If you do, you'll mess up your signal light circuit, the result being both trunk lid brake light filaments blinking when the right or left fender brake light is blinking, depending on which (left or right) filament you tied into.

Edited November 29, 2009 by Mel

[Bob Fouts]

Looking at it a little more, it would seem that the brake lights are designed to only operate on the taillights in the rear fender and the turn signals are designed to only operate in the trunk lights. Is this the way all avanties of this vintage work or do I have something unique?

[Gunslinger]

That can't be correct for them. Starting in 1968 all cars had to have turn signal lights visible from the sides, so the trunk lights being the only turn signals is not correct. You don't have something unique...you have something wired incorrectly. Since I'm not all that familiar with Blake era Avanti's with the backup lights moved down low and the trunk lights changed to red lenses, but it makes sense that the trunk lights should at least be brake lights. Maybe the body mounted lights could be the only turn signals...maybe someone with an '85 can correct me on that.

Look inside the sockets of the trunk lights...are there two contacts in each or only one? If only one, they may be brake lights only. If there's two contacts in each, they would be both brake light/turn signal and running lights. Make sure you have the correct bulb in each.

Do the backup lights work correctly? If not, there might be a problem with mixed wiring. It's possible your car was originally a standard trunk mounted backup light system that was modified by a previous owner and performed a poor wiring installation.