Rear Window Defogger

I have a 99 Alero GL. My rear defogger willl not work at all. There seems to be power cause when I disconnect a contact on the window and reconnect, I see a little spark. The light on the switch turns on then after time turns off. It just doesn't defrost at all!!! Do anyone know where I can get the wiring diagram or has anyone seen this problem before?

if you still need that wiring diagram I could probably dig one up for you. let me know.

Can you tell me if you got this problem fixed and how... I think I have the same problem. Thanks
Chilie

Any solutions for this, it just happened to me this weekend.

I have an 02 with 30K on it and on my rear defroster, it only clears about half of the window, usually melting snow/ice at the middle of the glass, but not on either the left or the right side. Let us know what's up.

Jeremy

I have a '98 Malibu LS, that's had EVERYTHING go wrong with it. Granted, it's not an Alero, but there is a family connection.

Last summer the rear defroster quit (which in South FL, I do use in the mornings to clear the mist). Solution was, believe it or not, a new rear window.

Thand GOD I still have the Extended Warranty in force. You don't want to know how much that would've cost. Yikes.

Just an idea, hope that's not what's up with the Alero.

I had to replace the module for the defroster.You might want to have a look at it...they get hot! the plug was melted on mine! Good Luck.

where is the module located. How much to replace?

Well on the ones that clear half way normally it is those thin painted on like grid that gets scratched from cleaning and the loop gets broken. Where ever the frost line doesnt clear start checking those lines for a break, normally a scratch in it. At a good automotive parts store you can get a tape or a paste to fix it. Normally the paint on paste works well but remember to tap of the area so you keep the same little line. If your getting power to the grid then it normally will be a problem like this. Its surprising that these will peel and just from cleaning the window this will happen also.

Good Luck

P.S. The other issues sound right about overheating in the module and plug mealting another idea might be checking for lose ground. just a thought..

where is the module located. How much to replace?
passenger side between back door and rear window. the molding comes off.i think you have to put the back seat down first.it cost about $180. CDN. just look where the wires come out.my sis-inlaw had her's replaced to.

I had to replace the module for the defroster.You might want to have a look at it...they get hot! the plug was melted on mine! Good Luck.

I had exactly the same problem with my 99 Alero, the plug had melted on mine as well, and I had replaced the module, but now it's gone again, and I am afraid that I will have to get them to rewire the system, unless I can just cut the plug off and replace it.

yea its the rear "black box" GM part # 22618677 and the wire usualy melts 2 GM part # 15305949...total cost 130.95 in buffalo ny....good luck everyone!

Can you just replace the two "black boxes", or do you have to replace the entire back window and defroster assembly?

Jeremy

Can someone email me how thy fixed this problem. I got a new relay, put in a new fuse, checked the connections on the rear window and still nothing. Please email at bdude13@yahoo.com how you fixed the problem as the weather in Chicago sucks. Is it omething that can be done at home or do you need to be taken in to a shop. also where is this part that people are switching located and how do I get to it?

This is pretty easy to fix. What happens is the connector to the black box gets hot...it isn't that good of a connector to begin with. Anyway, the connector heats up, and melts the plastic connector going into the box. When the plastic melts, the pins separate, and the connection is even worse, so it gets even hotter. Eventually they separate enough that the connection is lost and the defroster doesn't work at all.

There isn't a problem with the black box though! If the terminals are melted a little it probably doesn't need to be replaced. I just cut the (ruined) connector off, took the black box apart, and soldered the green and black wires directly to the pins inside. It doesn't take too long, and doesn't cost anything, and that connection won't fail again.

The reason it fails again for some people is that the connector is ruined the first time it happens. Even with a new box, the connection will be bad if it works at all, the terminals will heat up again and you still have the same problem. At least replace the connector if you are going to try to fix this. If you solder it, make sure you get a good connection on the larger black wire, there will be a lot of current going through it for the defroster...that is why the connector melts in the first place.

The box is located in the pillar between the passenger side window and the rear window...right below the two defroster connectors on the passenger side of the rear window. Those two wires go into this box, about six inches away. You'll have to remove the three panels in the rear on the passenger side...I was working on a two-door Alero so a four door might be different. I had to remove the passenger side seatbelt hoop and the coat hanger hook in the rear. You need a large torx socket for the seatbelt, and a flathead screwdriver for the coat hangar.

If you still have any questions let me know...it isn't hard to fix. It took maybe an hour, and I didn't really even know what I was looking for when I started.

steve@wotelectronics.com

I had the same problem the my 1999 GLS. Luckly for me it failed under warranty and after the seconf trip to the dealer they replaced the Module. I believe it was under the head liner in roof of the car.

I found a fairly complete, inexpensive repair manual to be the Haynes 38026. I use it for troubleshooting and repairs.
It costs about $20 at parts stores in Ontario Canada.

You can find GM parts 22618677 and 15305949 for about half the list price at gmpartsdirect.com. The module is about $55 and the connector is about $13. Please post any cheaper prices if you find them. I am having the same problem with my 2000 Alero. I had the module replaced under warranty but it went out again.

You can find GM parts 22618677 and 15305949 for about half the list price at gmpartsdirect.com. The module is about $55 and the connector is about $13. Please post any cheaper prices if you find them. I am having the same problem with my 2000 Alero. I had the module replaced under warranty but it went out again.

The problem is the connection, not the module. The connector can't handle the amps being put through it, and it overheats. Solder the wires to the terminals in the module instead of using the connector, and you won't have this problem again.

There is no cost if you already have a soldering iron. If you don't, go buy a good adjustable one for $50 and you'll still save $30, and you won't have this recurring problem. Use heat-shrink tubing or a couple of coats of "Liquid Electric Tape", NOT normal electric tape, that stuff is crap, and should only be used in temporary connections.

Thanks. I'll give that a try. I already have a soldering iron so maybe I can fix it for nothing.

The problem is the connection, not the module. The connector can't handle the amps being put through it, and it overheats. Solder the wires to the terminals in the module instead of using the connector, and you won't have this problem again.

There is no cost if you already have a soldering iron. If you don't, go buy a good adjustable one for $50 and you'll still save $30, and you won't have this recurring problem. Use heat-shrink tubing or a couple of coats of "Liquid Electric Tape", NOT normal electric tape, that stuff is crap, and should only be used in temporary connections.


SteveR -
I clipped the half-melted connector from the wires and soldered them directly to the module, as you said, and it works perfectly! Finally I have rear defrost again. I also used heat shrink tubing for the first time and will never go back to electrical tape. Thanks for all your help, I really appreciate it.

You shouldn't have any more problems with it.

As for heat shrink tubing, if you ever want to make a good water-tight connection, use heat shrink tubing and liquid electric tape. Coat the soldered connection with liquid electric tape, then slip the tubing over the connection and shrink it befor ethe liquid electric tape cures. It produces a very tough water-tight electrical connection. I'll usually use two layers of heat shrink, shrinking them one at a time. Makes a connection that is stronger than the original wire.

I had the same issue with the rear defrost. The Dealer had charged my $110 to replace the Defrost/Radio module. After 11 months I started smelling a burning plastic odor. This Really freaked me out! I would always spazz and start to sniff everything, but I could never find it. Once morning I noticed the defrost wasn't working. So I changed the relay without any results. So I Bought a big Torx Fitting for my ratchet and then removed the Passenger side seat belt. Then use a tiny flat head screw driver to pull out the center of the hanger hook. As soon as it is free the hook will drop down. Everything will pop off just Pull. Some of the plastic clasps might break but try not to break too many. Disconnect the module and then unmount it from the vehicle. The connector will be Unusable. Just cut off the connector. Use a knife to cut the corners of the module only one side. Fold it over and you will see the two male prongs. Solder heavy gage wire onto each of the two prongs. Use the old connector to reference which wire connects to each prong. Close up the module with Super glue or Black Tape. Reinstall it in the vehicle. Strip the wires from the module and the vehicle. DO NOT BLACK TAPE THESE CONNECTIONS. Instead use butt connectors. That should solve the issue.

Here are some images. If no images then HTML is disabled so just copy and paste the address

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Now I just have the problem of my car stalling and not starting. What junk. lol