Its finally getting cold down here in GA, and ive run into a problem, my rear defrost doesnt seem to work. This is my first winter with the car so i have no idea if it worked before, and i hate to say it but im not really sure how it works or if it even exists. Background: I bought this car a few weeks ago and its been rigged a bit, the guy must have been having problems with the heater/vent control unit, and seems to have bypassed all the controls, leaving it in defrost at max speed all the time with only the lever for cold/hot temp open for adjustment. He re-wired it to a toggle switch that when turned on runs it at full speed, when fliped off turns it off, somehow he managed to wire the switch to where it is able to be turned on whether the car is on, off, or even has no keys in it. While replacing the dead rear hatch lifts, i discovered wiring on the passenger side strut that connects to tabs at the top and bottom of the lift, im fairly certain that the hatch has defrost due to the rear windshield having all the grids and such that you'd see in a normal rear defrost window. But there is no defrost switch or button in the car, and i looked a bit for wiring on the driver side lift, and couldnt see any, but it may be tucked back under the plastic, or may have been cut . If anyone could give me some insight on discovering if this hatch had defrost or not, and if it did, how to get it working i'd be greatly appreciative. Also, if anybody knows where to get a NEW heater/vent/defrost control unit id be thrilled (i want to restore it back to pre-toggle switch on/off mode) The car is an 87 camaro, i believe stock, with no upgrades whatsoever. Thanks in advance for the help,

Joe

 

sucks to hear about the situation. The wire you mention, is it stuck to the line grids on the window, or are you referring to the end where it attaches to the car? There should be 4 wires total on the back. 2 per hatch strut and one on each end. Once you complete the full circuit you should be able to just turn on the defrost (via a button). I'm not sure where you can get new parts around here, but the PullAPart has like 5 Camaros you can pull from. Including a Berlinetta with a digital dash...

 

Ive got one wire, its only on the passenger side of the hatch, and it does have two wires, one attached to the top, and one attached to the bottom of the hatch strut, and they seem to run into the plastics and then attach to the glass via a wire. But i cant find the same parts on the drivers side (by parts i mean both wires, the ones at the top, and those at the bottom. I may have to take a ride down to pull a part and hunt. Thanks for the help, nice to see another person from Augusta on here, glad to know im not the only one with taste in beautiful american cars, not sitting on rims the size of the moon.

 

yeah. There should be one wire at the bottom of each hatch strut and one wire at the top that connects them to the glass...

 

One of the more common and annoying, though not critical, failures in the 924 is the lack of working rear defrost. Fortunately the system, though electrical and easily susceptible to gremlins, is simple and easy to diagnose and fix. Power is supplied via a relay back to the left-hand side of the hatch, then grounds on the other side of the hatch.

 

Anybody have basic advice for "rewiring" the system? I have the passenger side (i guess the ground?) But somebody must have decided that the wires on the drivers side didnt belong, so i need to rewire from there all the way to the front. There is no defrost switch, and if there is, where would it be? I cant find one anywhere. Anybody have a diagram of how this should be wired?

 

 

im wondering about this aswell, because i also have the grids on my back hatch window but have no switch to turn on the defroster

 

Did someone replace the hatch on your car? If you don't have wires running to and from the hatch struts and nothing on the dash, I would lean toward this possibility. It would be a bit strange for someone to replace the dash-mounted switch with a dummy panel just for the heck of it, but I could certainly imagine someone needing to replace the rear glass. They may have pulled it off a car that originally came with the defrost option.

 

i have the wires, and i called the PO who was the second owner of my car and he said its all factory and he has never changed anything

 

To me it sounds like you guys cars might have come without rear defrost but the hatch was replaced. Think about it, why the hell would someone take out the switch for a rear defrost? I think it's more likely that the hatch glass was broken some how and replaced with a used one that had rear defrost. My bird is the other way around, came with it from the factory but the replaced hatch doesn't have it. If you do a google search there's a company that sells aftermarket rear defrost kits and I think that you can buy just the switch and wiring from them.
Good luck
Alex

 

the switch is suppost to be below the lighter right?

 

Yes. It's a single switch with a little built-in light to let you know that it's on.

 

yep, my car doesnt have the switch

 

is there wires behind the panel? if not then then the car didnt come with defrost. how ever im unclear bout one thing. the wires onthe passenger side, you have one connected to the bottom of the strut but at the glass is there a wire from the glass tot he strut? if so im gona say the 1st owner replaced the hatch. if not then the hatch could be orginal ( my 88 camaro had pinstriped glass so it looked like it came with the deforster) and some one replace the struts witht he wrong ones.

umm also a thought...check the rpo codes? the best way really to see if it came with it. umm i dont now the code maybe some one else does.

 

Well, the P.O. decided it'd be cool to do an A/C delete and wire the On/Off switch for the heat to a toggle switch right where the defrost switch should be. For the time being, ive been using those Rain-X anti fog wipes, which work very well for my situation. Being in GA, im only worried about no defrost for about 3 months out of the year, so i can deal. Thanks for all the great help.

 

wooooowwwwww. but always glad to help.