Rear Wimndow Defrost not working

[JochenWoern]

Well, I guess I am starting to realize HOW LUCKY I am to be living in Northen CA. The last week we had overnight tempartures in the 20's, which is pretty darn cold for around here.

-----> Yes, I realize that this is not cold to the rest of the country on the East Coast.

Never the less, ever since it is cold there are all kinds of things happening to the truck. Noticed some leaky oil or tranny cooler lines, rear heater is acting up again after I just changed the Blend Door in July, as it was only blowing hot air. Fixed it and the air was blowing cold, now the heater does no longer want to work and it is blowing cool air in the back. I am thinking I might have to check all my actuators as I believe these no longer properly open and close for the set temperature anymore.

Ok, but now to the Rear Deforst. When I hit the button on the dash, the light on the knob comes on and I also hear the relay "click", but it does not appear that the rear window is getting heated.

Any thoughts?

Thanks for the help guys.

 

[BirchyBoy]

I'm not familiar with the NBS, but the OBS has "rods" that make contact between the body and the rear door when it's open. These "rods" lose conductivity and need to be cleaned with emory cloth or light sandpaper.

 

[JochenWoern]

I'm not familiar with the NBS, but the OBS has "rods" that make contact between the body and the rear door when it's open. These "rods" lose conductivity and need to be cleaned with emory cloth or light sandpaper.

There are two connectors at the rear window that plug into the wire coming from the ceiling.
Are you suggesting that I unplug these connectors and clean the tabs that are connected to the rear window heater, then re-connect?

 

[BirchyBoy]

There are two connectors at the rear window that plug into the wire coming from the ceiling.
Are you suggesting that I unplug these connectors and clean the tabs that are connected to the rear window heater, then re-connect?

No sorry. The OBS (barn door model) has pins that make contact when the doors are closed. Yours must be different than this.

Sorry for the confusion.

 

[JochenWoern]

No sorry. The OBS (barn door model) has pins that make contact when the doors are closed. Yours must be different than this.

Sorry for the confusion.

YES. I rememeber that when I had my '99 Tahoe.

BEST TRUCK EVER overall, should have never gotten rid of it and should have drove it to the ground.

AND, it did not have all these electronic gadgets like the Auto Climate Control which never wants to work.

 

[Yukongk]

Wish I could be of more help, but I remember seeing a thread about this and IIRC the wiring for this and the OP's rear wiper had a bad ground. Hopefully, someone can chime in.

 

[Rivieraracing]

Are your side mirrors defrosting when you push the button? And you say knob, do you mean the right most button on the climate control?

 

[JochenWoern]

Are your side mirrors defrosting when you push the button? And you say knob, do you mean the right most button on the climate control?

Yes on both Chris.

Sorry, the German said knob, but meant button. After 25 years I still do not speak it fluent. ;-)

 

[Rivieraracing]

Yes on both Chris.

Sorry, the German said knob, but meant button. After 25 years I still do not speak it fluent. ;-)

No biggie, was just making sure that the right stuff was being turned on which I figured it was! Might not be a bad idea to check for voltage at the rear window to see if you are even getting juice at the window when the button is pressed!

 

[JochenWoern]

No biggie, was just making sure that the right stuff was being turned on which I figured it was! Might not be a bad idea to check for voltage at the rear window to see if you are even getting juice at the window when the button is pressed!

So what if there is no juice? Then what? Since the mirrors defrost, the button obviously works.