How To: Fix rear window defroster [Archive]

View Full Version : How To: Fix rear window defroster

Redog

01-03-2009, 10:16 PM

I did it today, boy it feels good to have a rear window defroster after being broken for about 5 years. I just wanted to know how to do it before tearing into the job, plus I always thought it was the modular itself that was bad, but it's the plug that melts causing the defroster to not work

Tool for the job.

Breaker bar (3/8 drive)
10mm socket (1/4 drive)
1/4 drive socket
3/8 drive socket
t-50 socket (3/8 drive)
Thick pilers
small screwdriver
wire stripper and connecters for no soder

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1254.jpg

and for sodering
Sodering iron
Thinest electrical soder as possible

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1255.jpg

Remember some steps are for 2 door models only ;)

1. (2 door model) Use a T-50 to remove the seat belt bolt, use a breaker bar if necessary, it will move

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1226.jpg

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1227.jpg

2. Use a small flathead screwdriver to pry out the plastic pin holding in the coat hook.

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1228.jpg

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1230.jpg

3. Fold down the rear seat.

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1225.jpg

4. Gently pull the trim piece away from the body. Work around the edges.

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1231.jpg

5. (2 door model???) Pull out this small panel. This prevented me from pulling the panel completely off the body. This has the hinge bar going thru for the fold down seats. Just pull and leave hang

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1232.jpg

6. Now you can see the mod on the "C" pillar

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1233.jpg

7. Unplug the window connectors

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1234.jpg

8. Unplug the main plug from the mod. I pulled mine thru the seat belt area.

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1235.jpg

9. Use a 1/4 drive socket and a 10mm socket to remove the bolt from the body

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1237.jpg

10. Pull the mod down and out from the seat belt area, and unplug the radio antenna

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1238.jpg

11. Now both plugs are free

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1239.jpg

12. As you can see in step 8, the plug is melted away.Now you can cut the plug off and go to Step 13, or you can do this for sodering. Get the small screwdriver you used to remove the coat hook in step 2, and jam into the sides of the remaining plug. If it's melted away, it should be easy to break.

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1242.jpg

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1243.jpg

13. To finish the job, a nice beefy pair of plyers to crack the casing off

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1240.jpg

14. Remove the plug from the wires. You are not reusing the plug so it doesn't matter if you break it, just don't break the connecters inside it.

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1244.jpg

15. Open the mod around the egdes with the same small screwdriver. I bought another at the junkyard beforehand becuase I though the mod was the problem

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1246.jpg

16. Take off both sides until you see the board. Don't lose the rubber piece for the window plugs. Be sure to put it back in later

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1247.jpg

17. You can soder the the termials. The black wire goes on the right side, and the green goes on the left.

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1249.jpg

18. Be sure to remove as much of the plug from the black wire as possible. Use a small screwdriver, or wire brush to do the job, take care to not damage the plug.

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1248.jpg

19. While working, you can use the seat back hook to hold up the mod. Just put the wires in the hook

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1251.jpg

20. I wasn't happy with the sodering, so I cut the plugs off as close as I could, stripped the wires, and put connecters on them. I took care to put the connecters on in such a way that if they disconnected, they wouldn't touch the other side. I also put a small piece of electrical tape around the green wire's connceter.

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1253.jpg

21. Put everything back in reverse order. Be sure the wires don't come unpluged while putting it back. You can use electrical tape to tape the body of the mod closed, or to tape to the body of the car. Be sure the bolt is tight and the hook is back in the hole. I believe this is grounded here.

It works in my car now, going to keep an eye on it and make sure it's OK!!

After the job is done, band-aids and Neosporin

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1256.jpg

Midgear

01-03-2009, 11:09 PM

ah ha! so its the plug that melts!

i've been trying to figure out what the hell is wrong with mine-

Oldsman

01-04-2009, 07:48 AM

thanks a ton, Ken. this winter I will have to pull mine apart to see is same things is wrong with mine.

Vic28

01-04-2009, 08:51 AM

Pretty nice How To. I had to replace mine also once I got the car few months back. Atleast you were lucky that it was the only plug, mine melted on both places. So for those that have a problem, check first ;)

cherrington17

01-04-2009, 08:55 AM

Wow, ken did a how to!! AND has mostly non blurry pics for small pieces. I'm impressed. Good job,thanks for the addition.

Btw, it's solder not soder. I :lol: at the cold heat though... I hate those things, but good to know some people use them

Vinalero

01-04-2009, 12:58 PM

Yeah, I changed mine about one year ago, But I didnt have a T-50, so I just pried the trim and went under it without really seeing anything, fun stuff.

Mine was also melted in both places, had to change them both.

I will probly run into the same problem again, because I just put a new connector in.

Redog

01-04-2009, 02:10 PM

cherrington17

01-04-2009, 08:49 PM

they(coldheat) are good for joining two wires... and thats it.

and they eat batteries quicker then digital cameras.... :glare:

Redog

01-04-2009, 11:31 PM

I just didn't want to use a real soldering iron in the car. Might burn the carpet ;)

99alerogirl

01-04-2009, 11:50 PM

Wow nice, I'm gonna have to check mine out... It hasn't worked since I got the car :(

black

01-05-2009, 02:18 PM

great job!!!!

Redog

01-05-2009, 04:17 PM

*UPDATE*

Tried it last night, not too much fog on the windows, but it clearing it up in about 2 mintues. Didn't smell any burning, however I'm still keeping an eye out, or should I say nose :p

cherrington17

01-05-2009, 10:41 PM

:lol: i could just imagine linda freaking out as you crawl outta the driver's seat to go take a look at it... while on a busy highway....

Redog

01-05-2009, 11:41 PM

:lol: i could just imagine linda freaking out as you crawl outta the driver's seat to go take a look at it... while on a busy highway....

Meh, she doesn't like riding in the Alero, but that would be funny though ;)

Nate's Alero

04-12-2009, 11:07 AM

sorry about reviving an old thread,

can you just buy the new connectors? do we have a part #?
i dont want to solder.... i know mine has not worked in years...

cherrington17

04-12-2009, 11:11 AM

if you can solder it together... why bother buying the parts? solder is like... 1.69 for a big tube of it. it would take... maybe... 5 minutes.

Nate's Alero

04-12-2009, 11:14 AM

if you can solder it together... why bother buying the parts? solder is like... 1.69 for a big tube of it. it would take... maybe... 5 minutes.

then have a mini electrical storm behind my seat!!!! what if im doing something!?!?!?!?!

cherrington17

04-12-2009, 12:00 PM

electrical storm? your soldering 2 wires and then just putting a little tape between them to prevent them from touching.

done.

mrmike

09-06-2010, 08:56 PM

mine got really burnt. it melted the plastic casing and there was melted solder in the bottom of the case as well. Should I try to hook it up to see if it works or should i just get a new one?

Redog

09-06-2010, 10:44 PM

If you can get the melted plastic off the prongs and wires, I say solder

mrmike

09-07-2010, 12:26 AM

Ok thanks for the writeup btw

jhubbz

12-03-2010, 04:02 PM

Just did this, hopefully it worked... I did kind of a shoddy job. the plug was hardcore melted lol. This was a lot easier than I thought it would be. You can just pull to molding off in sedans. No need for unbolting stuff

cherrington17

05-16-2011, 04:37 PM

I'll add my pics since I just did this. In case anyone wanted to see it done a slightly different way.

... If you can't follow the process... slap yourself. This is easy to do.

http://i178.photobucket.com/albums/w246/cherrington17/CIMG1592.jpg
http://i178.photobucket.com/albums/w246/cherrington17/CIMG1593.jpg
http://i178.photobucket.com/albums/w246/cherrington17/CIMG1594.jpg
http://i178.photobucket.com/albums/w246/cherrington17/CIMG1595.jpg
http://i178.photobucket.com/albums/w246/cherrington17/CIMG1597.jpg

(Tinned wires.. its kinda hard to see)
http://i178.photobucket.com/albums/w246/cherrington17/CIMG1598.jpg
http://i178.photobucket.com/albums/w246/cherrington17/CIMG1600.jpg
http://i178.photobucket.com/albums/w246/cherrington17/CIMG1601.jpg
http://i178.photobucket.com/albums/w246/cherrington17/CIMG1603.jpg
http://i178.photobucket.com/albums/w246/cherrington17/CIMG1604.jpg
http://i178.photobucket.com/albums/w246/cherrington17/CIMG1605.jpg

Baracuda96

05-28-2011, 07:48 PM

Thanks for posting this - the defogger blew at the end of winter this year and I haven't needed it since, but thought that I'd have to take it to the dealership to get this fixed. As it turns out, it'll be just a job that I can handle. It's nice to see that some of the original members here still have their cars. :) Almost 250K Kms and my car's still running as if it were new.

foxsdaddy67

09-10-2011, 10:29 AM

Just did this to my car. man that plug just crumbled when i pulled it off. was an easy fix, just used new plug ends and taped the hell out of it :lol:

Redog

09-10-2011, 02:06 PM

Update on mine.

Still works fine :D

zearchyo

09-10-2011, 02:36 PM

im gonna try pulling this done to and if not tomorrow

Papa Rad17

09-11-2011, 06:42 PM

http://i18.photobucket.com/albums/b112/ThaCrib/DSCN1225.jpg

is that hint of noss I see?...lol. thanks for the write up, I know what im going to be fixing!

cavaliers60

09-20-2011, 09:58 PM

^^ No, it's his air tank for his train horns. :)

Papa Rad17

09-20-2011, 10:08 PM

Oh... Um... Well that works to. Lol. I'm about to go out and fix my defoger right now. Thanks for the write up!

colonel6632

09-20-2011, 10:35 PM

ive gone 3 winters without this. hopefully i remember to do this soon. thanks for the writeup

Papa Rad17

09-21-2011, 12:24 AM

update, just got it done/fixed, WORKS GREAT! my plug and a large portion of the case was roasted around it... strange, good one GM! ion and reddog- pics helped a ton. thanks!

Hellfire5670

10-26-2011, 08:03 PM

AH HA! This is whats wrong with my Read Defog! Maybe i can fix this while my car doesn't run

Shy

02-13-2013, 09:52 PM

Fixed my rear window yesterday, and now it works great. Thank you to the OP of this thread and to the creator(s) of this forum. Saved me I don't even want to know amount of dollars at the GM dealership.

Papa Rad17

02-14-2013, 09:59 AM

^Agreed. Iv used this write to up to fix the defogger in 3 aleros so far. Dealership wanted to charge $150 to fix it for a friend. :lol: I just told him to get me a new role of duck tape.

Redog

02-15-2013, 02:53 PM

Still works.

Still find it funny that Chris HAD to post up a way to do it. :rolleyes2:

Guy thinks I'm a moron just because I don't have a college degree :rolleyes2:

03glgold

02-15-2013, 04:01 PM

I have one college degree and I am taking physiology and a few other medicine related classes while working on my second degree...do I get to talk down on everyone yet :p

Redog

02-18-2013, 03:50 AM

I met you, you're not a smacked ass ;)

thegoat54

02-19-2014, 08:43 PM

I just cut the thicker wire and bypassed the module all together. Defrost works again.

I left the other wire unhooked too. What does this thing even do? My radio reception has always been bad in this car.

Redog

02-20-2014, 09:45 AM

Nas Escobar

02-20-2014, 05:20 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, 09:46 AM

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, 07:37 AM

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, 11:55 AM

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

Papa Rad17

11-28-2014, 05:22 AM

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

DaRockwilder

10-13-2015, 09:43 PM

Papa Rad17

10-14-2015, 01:03 AM

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, 03:26 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, 05:06 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, 05:51 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 :awesome:

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