Rear Defogger

[3.4Alero]

Originally posted by Oldsman+--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Oldsman)</td></tr><tr><td id='QUOTE'>Does anyone have the electrical schematic for the defogger. Mine isn't working and need to trace down where the problem is.

Fuse is good.

Is the relay for the defogger a solid state relay?

I imagine the coil for the relay is a 12v coil and when you press the defogger button this energizes the coil.

So I need to check to make sure the coil is getting energized and if so then check to see if power is actually coming out of the relay.

So any help would be great.[/b]
Originally posted by misslindseysue+--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (misslindseysue)</td></tr><tr><td id='QUOTE'>I dunno, but let me know what you find. Mine isn't working, and no one answered my question about it. I have power everywhere but the at the window, so I'm going to have to tear the damn car apart before it gets too much colder. [/b]
Originally posted by Voodoosoup
Mines broke too, haven't checked it out yet but here are the instructions from the Haynes manual.

1. Turn the ingintion and defogger switches to the ON position.
2. Using a voltmeter place the positive probe against the defogger grid positive terminal and the negative probe against the negative terminal. If battery voltage is not indicated, check the fuse, defogger switch, defogger relay and related wiring. If voltage is indicated but all or part of the defogger doesn't heat proceed with the followiing tests.

I'll post the rest later if it is needed. Because It's a little longer than this first part!
Originally posted by 99alero
mine didnt work in my cutlass cause i had some of the lines scratched on the window. but i have no clue
Originally posted by noodle
couldn't find a diagram but here's the troubleshooting from GM manual
Originally posted by traneld
Try checking the connection block at the back window with a multi meter. That is where my defog failed. the connection in side the block failed and you can't tell without removing it.
Originally posted by misslindseysue
Just wanted to say that mine is working now. It must have gotten jarred during the amp install, 'cause we just took all the plastic off, wiggled all the connections, and voila, it works.

Hope yours was as easy.
<!--QuoteBegin-velocity@
I've got the same problem, I'll be looking at it this weekend when I get a chance. I'll let you guys know what I find. So far I know that the fuse and the relay are good but I'm not getting any power at the defrost connector.[/quote]
<!--QuoteBegin-velocity
So Last year the same thing happened to me, rear defrost all of a sudden stopped working. I took it to the dealer and they replaced this module that controls the rear defrost/antenna array. Well I found it, on the passenger side C-pillar, under the plastic trim. Turns out it had melted to poop, so I just bypassed it and both therear defrost and the radio seem to work fine now. So if you are having problems with the rear defrost not coming on at all and the fuse and relay are fine check that module.[/quote]

[flalero]

Man, it's about time I find an answer to this problem. My defrost hasn't been working since I bought the car. I'll try the bypass solution.

[Oldsman]

well i replaced the relay and fuse. I am going to just double check the switch and make sure it ohms out good. I will check this module also. I have noticed that radio reception is really starting to suck.

Who was it that did the by-pass????????

[Voodosoup]

Velocity is the one that did the bypass. I'm planning on checking mine out this weekend. It has to be this module on the c-pillar.......

[Oldsman]

Phil let me know the details on this.

[velocity]

One other thing I should add I guess, I got my rear window tinted with some metalized tint. It might be that the tint is drawing some extra current that the module thing wasn't designed for. It wasn't the actual module that melted it was the connector that plugs into the module, but I bypassed the module anyways and no problems so far and I've been using it every day for the past week or two.

[Oldsman]

was this under the front or rear pillar????

[velocity]

Rear pillar on the passenger side.

[Oldsman]

thanks

[bdyman]

maybe ya just cut the line in the window ever think about that one???

[Oldsman]

well mine is not getting any voltage to the rear window. but voltage is going to relay and the coil is being energized and the voltage is going thru the contacts so relay is fine, switch is fine so it has to be from fuse box under the hood to the rear window. I just have to track down where the voltage is dying out at.

[bdyman]

well that`s fine and i understand but, did you look at the lines in the glass?
if one line is cut nothing will work

[Oldsman]

yes i did and everything is good.

i have also noticed my recption has been going downhill so which leaves me to believe it is the module.

[Oldsman]

Well mine is fixed...............here is how I did it.

It was about 2 weeks ago.........

Went out to start the car, started it, frost all over windows, said F it, I'll try and see if this Fn things will work...............And It did.

The damn thing started working on it's own. Go figure.

But radio reception is bad so the module in the back is suspect.

[misslindseysue]

Heh. Must have wiggled the wire somehow.

[Oldsman]

probably my new sub and box fixed it..............LOL