I started taking my '88 GTA convertible to try tracking down some of the wiring problems I've been having. I corrected just about everything except for a few things:

1) I don't have a specific button for the tonneau cover release. What are all of you using?

2) My tonneau cover circuit runs from the release solenoids, through a switch on the pull down motor (to keep tonneau from being released while trunk is open), to nothing... I have not a clue as to where the wire going from the other side of the switch is, and where it's supposed to go to.

3) I still have the original rear defogger switch (on/off with light) in the dash. But, I can't seem to find where the wires go to. They disappear behind the dash. In searching through the wire bundles that run along the side of the car, under the carpet, I can't seem to find the black wire that originally went to the defogger element...

Thanks ahead of time for any advice. - John '89 L98

 

The switch on the pull down motor is normally connected to the hatch release wire. You may run a wire from the switch on the pull down motor to the NO contact of a relay. Connect the pole of the relay to accy power. Connect one side of the relay coil to the dark green wire from the PRNDD21 switch in the console. Connect the other side of the relay coil to one side of the new release switch. Connect the other side of the new release switch to accy power. The release mechanism will not operarte unless the gear selector is in P or N, in this configuration.

The defogger grid power wire is purple / white. It runs down the wire duct under the carpet, next to the drivers seat. What will you be using it for?

Tim

 

Tim, I'm not quite sure if you're suggesting that I install/wire-up a dedicated switch. If this is the case, I'd much rather keep the interior as stock as possible. With that said, I'd rather not put in a new switch.

If on the other hand you're suggesting I wire it up to the hatch release switch, I'd once again rather not do that as I enjoy having a trunk release in the car. I know I would easily be able to wire it up so that the "hatch release" switch would operate the tonneau cover release solenoids, but I'd rather find a separate stock switch to work it.

That brings me to the defogger switch. I was thinking that since I have no need for a rear window defogger (can you imagine the problems I'd have with my plastic window :-) ), I would wire up the tonneau release solenoids to the defogger switch. I believe the wire is indeed purple/white as it runs along the side of the car, but it changes to black down the line. The problem is that there exists not a single purple/white wire going to the rear of the car. - John '89 L98

 

I understand what you are after, now. Sounds like you will have to run a wire to the rear through the "added" reinforcements - it is a pain (on an '87 conv, at least)!

Tim

 

Oooh, ooh! Tim just gave me an idea. The power trunk release only works if the transmission's in Park, or if the handbrake's on, or something like that, right?

I'm too tired to think of the correct wiring schematic...but I think that using a relay, you could configure it so that when the handbrake's on, the trunk switch pops the trunk. But when the handbrake's off, the same switch will pop your tonneau cover for you.

If you can find the momentary wire coming from your defroster switch, you could probably use that too.

 

You could use the hand brake switch as a "selector" to determine which function the release switch would control, if the car is an automatic. With a manual trans, the hand brake switch is already used to disable the release relay so the hatch cannot be released if the hand brake is not applied.

Tim