How To: Fix rear window defroster - Page 3

Nas Escobar · 02-20-2014, 06:20 PM

You guys know if this is an Alero only thing, or did all GM cars have a similar module?

I ask because I know of 2 GM cars with no working defroster - My Camaro and a Cavalier that's owned by someone I know. The Cavalier's worked at one point, while idk what's up with the Camaro since I bought it like that.

zzyzzx · 02-21-2014, 10:46 AM

Quote:

Originally Posted by Redog

Yeah teh cold heat didn't do a very good job

Glad I just borrowed it

Those cold heat soldering irons have a well deserved bad reputation. Other than that, the writeup is really good. How common is this problem?

thegoat54 · 02-22-2014, 08:37 AM

Quote:

Originally Posted by Redog

Yeah, not a good idea

Why isn't it a good idea?

I'm guessing that this module is just the antenna booster to compensate for not having an actual antenna on the car?

Well I can't tell one lick of difference between my radio reception before or after by passing the unit all together.

I still left the antenna hooked up through the unit so it connects to the antenna in the glass, just don't have the power hooked up to it.

So that means that either this module never did anything noticeable for me, OR its been burnt out since I got the car (Got in used in 2004). I'm going to go with it doesn't do a damn thing because my defogger only stopped a year ago.

I say bypass the thing people. . . . . .

thanksman · 11-23-2014, 12:55 PM

thank you for taking he time for this. It made this very easy.
I did this just in time for a MN winter!

Papa Rad17 · 11-28-2014, 06:22 AM

This was the first thing I did on my new alero. perfect bump for the time of year.

DaRockwilder · 10-13-2015, 10:43 PM

2015 bump.

Were you guys able to get power at the connectors at all before doing this fix? I can get power at the connectors when I take a reading and the connectors are unplugged. As soon as I plug everything back in on the window, zero volts.

Going to pull the panel off and check the wiring there regardless, though.

Thanks!

Papa Rad17 · 10-14-2015, 02:03 AM

Quote:

Originally Posted by DaRockwilder

2015 bump.

Were you guys able to get power at the connectors at all before doing this fix? I can get power at the connectors when I take a reading and the connectors are unplugged. As soon as I plug everything back in on the window, zero volts.

Going to pull the panel off and check the wiring there regardless, though.

Thanks!

I dont know, never checked. I've done this on 4 different alero's and simply re-soldering the leads fixed them all. The strips on the windshield are probably just a small heating element like in anything else, thus you wouldn't see much resistance when looking at them by themselves. That being said, when you connect the leads into it, and turn on the power, current may be flowing but you aren't seeing voltage because the circuit has such a low resistance the neutral lead is equally as charged. No difference in potential, by definition- voltage. I can not guarantee that is what is happening there at all, you could just as easily have gotten something else hot and theres an actual short. I would believe either one, try it and see if you blow a fuse, you will have your answer.

DaRockwilder · 10-18-2015, 04:26 PM

Well, I pulled mine apart and sure enough, the connector was melted. However the module is also damaged, as there was solder flaking off the board. I'll most likely have to get a new module.

agencare10 · 10-20-2017, 06:06 PM

Hey, I know this is a few years old, but hoping someone could help me out!

I have a question about the rear defrost fix....I thought I had fixed it... and followed your directions perfectly, but for whatever reason it still is not working.

Here is what I have done..

1. Cleaned connections with rubbing alcohol

2. Sodered wires back to the connection as suggested (green wire on the left, black wire on the right)

3. i put the tab connectors back on the rear defrost and it doesn't work.

Here is what I have tested...
1. The relay - ensured that the relay is working great
2. I have used a voltmeter and tested the wires, the green wire is giving about 11.5 volts and the black wire is not giving anything...(what is the black wire for?)
3. Before putting the tab connectors on the rear window. I test the voltage of the connector. The connector to the green wire is showing 11.5 volts...the other connections is still not showing any volts, but I am assuming that this is for the radio?

As soon as I put the connection on the tab to the rear window, the voltage drops to about .3 volts and it does not heat up rear window...would anyone know why!? Bad module maybe?

Redog · 10-25-2017, 06:51 AM

GM loves using black wire for ground. Throws me for a loop everytime I replace a switch or outlet in my house, because in that case, black is "hot"

Are you sure it's not working? Is there ice, frost or dew on the back window? You are not going to feel the grid getting hot. Rear window defrosters don't work that way. You could turn it on and see how much your voltage drops on the entire car. Rear window defroster uses a lot of power

The "other" connection is for the radio antenna. It looks like an RCA jack

If all else fails, then yes the mod is probably bad