01 Tahoe... rear defrost not working

[Bedore]

I have a 2001 Chevrolet Tahoe. The rear defrost does not work (like pretty much everything else on this junk heap). I kind of need it for the winter here in Maine. The light comes on when I press the button, and the relay under the hood clicks when I turn it on and off. But the rear window does not defog. I checked the connection on the rear window and both tabs appear to be fine...and both connectors are fine as well.

Any ideas?

 

[chauncey0337]

Is there dew on your truck in the morning? May sound stupid but just trying to figure out how you know it's not working. Mine usually takes a few minutes to heat up.
Do you have a multi meter to test if the tabs are getting voltage?

 

[Bedore]

No dew in the AM yet, but tonight it was raining and the back window fogged up bad. Couldn't see out of it. Ran the rear defrost and nothing happened. It did nothing on my 20 minute drive.

I did go out after I posted this with a 12v test light. The tab on the passenger side is getting juice, but the tab on the driver side is not. I suspect it's probably a wiring problem and I think I will have to figure out how to get at the wiring somehow.

 

[chauncey0337]

Maybe the tab on driver's side is the negative terminal.

 

[Bedore]

Is one tab positive and one tab ground? I used the 12v test light and touched the grid on the window and it lights up everywhere I touch it on the grid...meaning that the grid def. has 12v going through it. Just puzzled as to why it's not working still. Might have to wait for some frost/ice to really try it out...although you'd think it would defog it when it's raining.

 

[chauncey0337]

You would think so. I wonder if it gets hot enough to feel a difference in temp.

 

[Bedore]

Well, my rear defrost is still not working and I have no idea how to get it working. Does anyone have any ideas?

 

[Bedore]

Would someone on here with a voltmeter be willing to test something for me on their ride? If your rear defrost works, could you put the voltmeter on both tabs on the rear window and tell me what they read?

On mine the passenger side reads 12v, the driver side tab reads 0. I am assuming it's a ground but need to confirm. I'd really appreciate it. Thanks.

 

[bankswood]

Well I thought I would try to help but I just tested both of my tabs and got 0 on both. I haven't had the Yukon long enough to use the defrost so I don't know if it is working. Tomorrow I will do some more testing

 

[chauncey0337]

ok, seems like voltage goes from switch to pass side, through the grid on rear window to drivers side, then to ground. On pass side I got 12+ v and on drivers side I got 1v. I'm thinking maybe your drivers side is not grounded. Check that wire. Let me know if you need any more measurements or anything.

 

[Bedore]

Thanks alot guys. I think the connector on the driver's side is not making good contact for ground...or whatever it's supposed to do. I will probably replace it w/ a new spade connector and see if that does anything. Will update accordingly.

 

[jhacker5150]

Thanks alot guys. I think the connector on the driver's side is not making good contact for ground...or whatever it's supposed to do. I will probably replace it w/ a new spade connector and see if that does anything. Will update accordingly.

Apologize for the random bump, but I'm running into a eerily similar situation with my 2006 Tahoe's rear defrost. Did a new spade work for you? Curious to hear what worked/suggestions. Thanks!

 

[BigWheelinBubba]

Just a possibility here, i have seen bad heater cores cause extreme fogging of the windows and the defrost will not clear them.

 

[Bedore]

Apologize for the random bump, but I'm running into a eerily similar situation with my 2006 Tahoe's rear defrost. Did a new spade work for you? Curious to hear what worked/suggestions. Thanks!

Nope, a new spade did not make it work unfortunately. I suspect the element itself is bad and in order to fix it would require replacing the entire window which I am not going to do. Had no defrost for 2 winters now. Do you use the glass liftgate a lot? I have read that sometimes by using just the window lift gate, the wires that connect to the spades on the glass could be too short (LOL GM) and put stress on the spade connectors which eventually break. You can try soldering a new connector, but in my experience it did not work.

I ended up buying a new vehicle and have to say that I love the ride and 4x4 of the Tahoe...but I have owned it for 2 years and have put more than $3500 into it in those 2 years and I am so glad it's now a lawn ornament and I don't have to drive it anymore. It still has a lot of problems and is now burning oil (blue smoke out the tailpipe) with 134k miles. Which sucks because I always changed the oil when the computer told me to and tried my best to take care of it and fix every little problem, even going as far as soldering new lights into the climate control board so I could see all the buttons light up at night. Oh well.