Rear Defrost

09-26-2005, 05:29 PM

My rear defrost stop working sometime this summer? Perhaps the relay is bad. Also I was wondering if anyone know of a ground wire for the horn. My horn works intermittently and my Father seems to think that they is a ground wire that connects to the firewall. Thanks any help please

09-26-2005, 05:54 PM

Don't know about the horn (mine started working again when I replaced the battery), but for the rear defrost, the likely culprit is the little box hidden behind your passenger C-pillar. This migraine clouds my memory as to the exact name of the part, but if you use the 'search' function here for rear defrost I'm sure you'll find a few threads about it.
Is your radio reception also a bit fuzzy? The antenna and defroster both go through the stupid module and it tends to fry. It's about $100 at your dealer. I have one in my car that I just haven't installed yet.

Molson · 09-26-2005, 06:16 PM

yup, mine went too. I have the spare parts, got em from the wreckers, just have not put it in.

doubleN0alero · 09-26-2005, 07:09 PM

why do you need the defroster in the summer? LOL. But, what they said...i've replaced it already on my new car.

alero440 · 09-28-2005, 08:25 AM

OHHH I thought I was going crazy. My rear defrost doesn't work either. so there is a thingy in the C-pillar that controls that... I'll have to look into that.

09-28-2005, 08:34 AM

As for any wiring, I can get any diagram on the puter at work. IE what color wires are what. I'll see if I can snag some print outs today.

09-28-2005, 12:19 PM

The wires are all black, as I recall. It's the only thing up there, just a little box with four wires plugged into it. The first time it went out I wiggled them and it started working again. I'm guessing I wasn't so lucky this time, so I bought a new one. Wholesale I think it was less than $60, but at the dealer it was $103.

Molson · 09-28-2005, 12:56 PM

5 bucks at the wreckers, for both modules.

alero440 · 09-28-2005, 02:30 PM

I have to go to the junk yard for an interior trim piece (Stupid drunks burning my car!

issed: ) so I'll look for that module thing while I'm there

09-28-2005, 02:35 PM

It's such a PITA to get at I didn't want to get one that was used, so I just bucked up for a new one. I haven't replaced it yet 'cause I'm afraid I'll screw up the tint pulling all the stupid plastic off.

09-29-2005, 11:50 AM

Thanks alot. I will check into that. I thought that the relay possibly went bad. gre0481 can you try to find for me where the ground wire is for the horn. My uncle when he was working on my car said that he found one that was loose and he tightened it back up, and the horn worked great for a few weeks and now it stopped working again. Thanks alot!

Molson · 09-29-2005, 01:34 PM

I changed mine last night, the trim is a PITA but not too bad, the relay was burnt. Works now tho!

dbailey · 10-24-2005, 12:59 PM

Mine fried, too! The rear defroster stays on as long as the switch is on. When there is nothing on the glass to melt, the wires melt due to overheating. I always thought the damn thing turned itself off after a preset amount of time. NOT!!!!!

issed:

misslindseysue · 10-24-2005, 01:06 PM

It should turn off after 10 minutes. We replaced mine yesterday. That thing is FRIED. I'll have to take some pictures of it, Pat pried it apart.

dbailey · 10-24-2005, 04:17 PM

Hmmmm. Maybe it does and if there isn't anything to defrost it fries really quick. Now I make sure I pay particular attention to when it has done its thing and turn if off.

xbxradxsx · 10-24-2005, 04:27 PM

Does anyone have tint on their rear window, and still use the defroster? Someone told me that it could cause the tint to bubble up, and I have been scared to use it every since I got my windows tinted.

misslindseysue · 10-24-2005, 06:23 PM

I don't remember if mine fried before or after I got mine tinted... but I turned it on yesterday and nothing happened. The only problem I can see is with metallic tint shorting it, maybe? But otherwise just the wires get hot, nothing to worry about. I'm sure there's tons of people here who use it with tint. I will as soon as it fogs up, that's for sure.

dbailey · 10-24-2005, 08:03 PM

My windows have been tinted for a couple of years now and I have had no problems at all.

10-27-2005, 09:54 AM

The rear defrost on my 99 Alero isn't working. I see from the other posts that there is some kind of device behind the "C-pillar" that is the usual problem. Can anyone advise me what this device is, what/where is the "c-pillar" and what has to be removed to get at it? Thanks.

dbailey · 10-27-2005, 10:04 AM

It's a relay behind that plastic piece above your right ear between your head and the rear window if you're sitting in the backseat on the passenger side. It controls your rear defroster and also the radio antenna. I'm sure there's got to be some destructions somewhere on our site that tells you how to get to it. My suggestion if it is not a fuse that is blown, would be after you replace the part, turn off your rear defroster as soon as it has done its job. If you leave the switch on supposedly it turns itself off at a predetermined point. Until it gets there though it is gonna be heating up with nothing to melt and that I think is what 's killing the relay sooner than it should. Good luck.