2006 Rear Defroster

Have an 06 Impala 3.5L. Rear defroster not working, but light comes on at button. Went and replaced relay at under-hood fuse box, but that didn't fix it. Are there any fuses or switches in this system (besides the relay)?
Can anyone thing of anything else I could check? I don't really feel like getting screwed at the dealer for something this small, but it's pretty important for the winter.

Have an 06 Impala 3.5L. Rear defroster not working, but light comes on at button. Went and replaced relay at under-hood fuse box, but that didn't fix it. Are there any fuses or switches in this system (besides the relay)?
Can anyone thing of anything else I could check? I don't really feel like getting screwed at the dealer for something this small, but it's pretty important for the winter.

the rear defroster is a resistor mounted on the rear glass...measure the resistance...if open you will need to find out where its broken....if its small you can use a conductive paint that will get it working again...Ive done this...auto zone had it..it looks like gold paint and it is expensive for the amount you get..

obviously measure for 12volts across the connectors...in/out...not body ground but across this window grid...

the rear defroster is a resistor mounted on the rear glass...measure the resistance...if open you will need to find out where its broken....if its small you can use a conductive paint that will get it working again...Ive done this...auto zone had it..it looks like gold paint and it is expensive for the amount you get..

obviously measure for 12volts across the connectors...in/out...not body ground but across this window grid...


Checked the resistance, wasnt open, looks good.
Not getting any voltage across the connectors. I'm wondering if there's more to the system than a relay, perhaps a fuse that's not so obvious?

Thanks

Checked the resistance, wasnt open, looks good.
Not getting any voltage across the connectors. I'm wondering if there's more to the system than a relay, perhaps a fuse that's not so obvious?

Thanks

so you lost the feed ..the best thing to do is review the owners manual to check exactly what fuse is feeding this,then see if fuse has 12volts on it..

If this is good then you must trace the wire back...also make sure that the grid wires have a ground on one...MEASURE THE VOLTAGE TO A GOOD METAL GROUND POINT...MAYBE THE GROUND IS THE PROBLEM..

There is a TSB on it:

#PIC4684: Rear Window Defogger Inoperative - keywords back defog defrost fixed glass stationary - (Nov 16, 2007

TSB states:
It has been found in some cases that there may be a terminal concern at C200. Inspect terminal D6, circuit 293, for being fully seated in the connector and for proper terminal tension. If there are no concerns with the terminals in C200 continue with the diagnostics in SI

This is inside the big body to Instrument Panel Connector - 40 cavities in this connector - Body wiring harness to the I/P wiring harness, behind the right front kick panel, below the I/P fuse panel

circuit 293 terminal D6 -- Purple wire
Rear Defog Element Supply Voltage

Looks like the Heated Mirror Fuse (10 amp) is your fuse of concern in the underhood fuse / relay center

There is a TSB on it:

#PIC4684: Rear Window Defogger Inoperative - keywords back defog defrost fixed glass stationary - (Nov 16, 2007

TSB states:
It has been found in some cases that there may be a terminal concern at C200. Inspect terminal D6, circuit 293, for being fully seated in the connector and for proper terminal tension. If there are no concerns with the terminals in C200 continue with the diagnostics in SI

This is inside the big body to Instrument Panel Connector - 40 cavities in this connector - Body wiring harness to the I/P wiring harness, behind the right front kick panel, below the I/P fuse panel

circuit 293 terminal D6 -- Purple wire
Rear Defog Element Supply Voltage



Do you have any more information about the location of this connector, terminal, and circuit? I have a '03 base and I've been without rear defrost for going on 3 years now.
Ogre

This is what happened in case anyone has a similar issue:
Terminal connection D4 at C200 shorted out and melted terminal at C200. Fixed it by splicing and bypassing around C200.

The term "shorted out" refers to 12v to ground-

Normally, burnt contacts mean a poor connection that arcs and can't carry the current, the arcing produces heat which melts the plastic connector enough until the circuit is completely open. There was most likely no short involved- this would have blown the respected fuse and led you to the circuit/answer sooner- This was simply an open circuit due to a poor connection.

Glad you found it and posted back your results.

This is what happened in case anyone has a similar issue:
Terminal connection D4 at C200 shorted out and melted terminal at C200. Fixed it by splicing and bypassing around C200.

c200 is a ground point and because these heaters use large current just a small amount of corrosion can cause these poorly designed connectors to fail to maintain the proper electrical continuity...

this post of your findings will help others..thanks for this info..

Do you have any more information about the location of this connector, terminal, and circuit? I have a '03 base and I've been without rear defrost for going on 3 years now.
Ogre

I have a 2006 that hasn't had defrost in 2 years. The dealer told me the rear window would have to be replaced. I said, yea right, and decided to live without, but I'd like to get it fixed if I can. I get lights on the dashboard switch but no defrost. Connector is good on the back window, fuses good, no breaks on the back window as far as I can tell visually.

I'd like to get more info as well on the location of the connector(s) to check.

I have a 2006 that hasn't had defrost in 2 years. The dealer told me the rear window would have to be replaced. I said, yea right, and decided to live without, but I'd like to get it fixed if I can. I get lights on the dashboard switch but no defrost. Connector is good on the back window, fuses good, no breaks on the back window as far as I can tell visually.

I'd like to get more info as well on the location of the connector(s) to check.


follow the wires back to to fwd part of vehicle...in the rear door area you should find these other connectors, if burn't/green replace these connectors...use a heavy duty crimp type and tape securely so moisture will not re damage this .....radio shack or an electrical supply store has good connectors to properly repair this..

In what side of the vehicle is this on drivers or pass. . My son is having the same problem. Thanks

In what side of the vehicle is this on drivers or pass. . My son is having the same problem. Thanks

follow the proceedure to trouble shoot...measure the heater grid resistance. measure for 12volts...also make sure one side of heater is grounded...then trace back wires for defect using the post info..

the ground issue is common ...

Come on, guys. We don't all have the tech manuals for these cars. We don't all work in a garage with access to these documents.
Most of us have a multimeter, soldering iron, crimpers, basic stuff; and enough knowledge to not hurt ourselves.
I have been fighting a battle with my rear defrost for almost 5 years now, finding something to check here or there, when I get the chance, or trying to trace wires when I get a chance, but I still have not fixed this problem with my rear defrost.
I have taken the rear seat out, laid in the trunk, and still I can't really trace the wires back without completely dismantling my wire harness from the trunk forward.
I asked for some help on locating the circuits in question a little over a year ago. All I got was pdigital telling us what circuit and terminal he had trouble with, and now jcat you tell us to trace the wire back.

Would someone please help me (and other future readers of this post) to locate the terminal or wires in question?
Thanks.

so with your meter what did you find..?

the vehicles change from year to year esp. on electrical wiring and ckts..

hard to say were it is exactly and describe the exact location..

if you have the basic tools and know how to use them this is a simple problem..

I like youtube, see http://www.youtube.com/watch?v=FSPdfjCbHX8

danielsatur,
I am going to be as careful as I can saying this, because I DO want help from anyone that can help, but please, don't treat me like an idiot before knowing anything. Please give me the benefit of the doubt.

jcat,
I have checked ground, I have checked voltage, and I have checked continuity for breaks. I have checked and double checked all of my connections, tightened, cleaned, etc. I posted this a while back http://www.automotiveforums.com/vbulletin/showthread.php?t=675572 to try to document my findings.
I have replaced the antenna module, replaced the relay with 5 different relays (same model), and even, in desperation, bypassed the antenna module completely. It is not the module, not the grid, not the wiring between them. It is not before the relay, as I have tapped off that with a jumper wire and gotten the correct voltage over and over. It is somewhere between the relay and the antenna module.

I still have the intermittent voltage to the grid. It comes on for roughly one second every 4-5 seconds.
Ogre

You arn't the only one with a rear defroster problem!
http://www.automotiveforums.com/vbulletin/showthread.php?t=974438
http://www.automotiveforums.com/vbulletin/showthread.php?t=973520

I'am sorry that you feel that way, there's some good ''Auto how to video's'' on youtube, that other viewers arn't aware of.


I suspect a bad ground, because you need alot of current for defrost.

You arn't the only one with a rear defroster problem!
http://www.automotiveforums.com/vbulletin/showthread.php?t=974438
http://www.automotiveforums.com/vbulletin/showthread.php?t=973520

I'am sorry that you feel that way, there's some good ''Auto how to video's'' on youtube, that other viewers arn't aware of.


I suspect a bad ground, because you need alot of current for defrost.

I understand that you are trying to help, but you are also assuming that I have a broken grid wire.
While this may sometimes be the problem for people posting on these forums, that is not my situation.
Thank you.

what were the readings ? example : the voltage at the grid when on goes to 13.5volts then to zero..repeats every 5 sec.

the heater grid resistance is 20 ohms. the ground connection at the grid is .02 ohms...the voltage at the ground connection at the grid is 3volts when the defroster grid has power.....


so lets stop the b/s and start with the details ....good bad checked this and that don't help us give you some direction...

so lets stop the b/s and start with the details ....good bad checked this and that don't help us give you some direction...


Indeed.

I will attempt to solve this problem myself. If I do find the solution to my problem, I'll post the solution to let others know what I discovered.

Thank you for the direction you have given. You've been very enlightening.

Indeed.

I will attempt to solve this problem myself. If I do find the solution to my problem, I'll post the solution to let others know what I discovered.

Thank you for the direction you have given. You've been very enlightening.


with the info given to you , this is not impossible ..I suspect you don't have a multimeter that is why your not giving any details on your findings.
with out these specific details , of the circuits condition , this is all guessing.at the issue you have that is causing the heater malfuction.

Picture the whole circuit!
Need a battery, fuse, relay, switch, load (grid), gnd, bcm, thermo sensor, and wiring.

The Body Control Module (BCM) knows!
If it's too warm outside, or a low battery, the BCM wont trigger the rear window defrost.

A bad thermo sensor will act like a open, or bad grid.
Use a electronic component coolant spray to simulate cold on your thermo sensor.

Picture the whole circuit!
Need a battery, fuse, relay, switch, load (grid), gnd, bcm, thermo sensor, and wiring.

The Body Control Module (BCM) knows!
If it's too warm outside, or a low battery, the BCM wont trigger the rear window defrost.

A bad thermo sensor will act like a open, or bad grid.
Use a electronic component coolant spray to simulate cold on your thermo sensor.

if you read his posting#17 he states that he has voltage at the grid..If he is in maine I can say it is cold enough, also I believe that there are,, NO temperature controls on the rear window defroster....

with his vague undetailed testing data I would GUESS he has a short circuit...

wife just called with same problem on her 2006 impala lt. I'll work my way through the post and see what I can come up with. Then on to fixing my 04 2500HD electrical issues!!!!:disappoin

There is a whits connector with a bunch of wire's goin to it( roughly 3inX2in) under the fuse box on the passenger side (inside the car, not the 1 under the hood), I had to bypass the wire there. I had the same problems as you's. Talked to a few people and called GM. They told me to just bypass that wire, it burns up in that connector(no recall) Just wanted to let you's know

There is a whits connector with a bunch of wire's goin to it( roughly 3inX2in) under the fuse box on the passenger side (inside the car, not the 1 under the hood), I had to bypass the wire there. I had the same problems as you's. Talked to a few people and called GM. They told me to just bypass that wire, it burns up in that connector(no recall) Just wanted to let you's know

After reading your post I decided to check this. I appear to have a brown wire that has a slightly melted sheath on it. Is this likely my culprit? I have checked everything I could think of until I found this.