88red4cyl Posted February 24, 2011 Report Share Posted February 24, 2011 The rear defroster on my wifes 06 Monte Carlo decided that it was going to quit working. We don't use the backseat for anything other than setting her purse in when we go somewhere, but I climbed back there anyway to check the connections. The wires look ok, and the connector is solid to the grid.. When you press the defrost button, the light pops on and stays on for its alloted cycle, and turns off again, but the grid never even gets warm to the touch... Where should I start looking first? Quote Link to comment Share on other sites More sharing options...
carkhz316 Posted February 24, 2011 Report Share Posted February 24, 2011 Relay or fuse. Quote Link to comment Share on other sites More sharing options...
AL Posted February 25, 2011 Report Share Posted February 25, 2011 x2 Quote Link to comment Share on other sites More sharing options...
88red4cyl Posted February 25, 2011 Author Report Share Posted February 25, 2011 Thanks guys, I will check it out tomorrow. I just assumed that if it was a fuse issue the light wouldn't illuminate on the button... Guess we'll find out, if I can find where the fuse box is in this car.. Quote Link to comment Share on other sites More sharing options...
Addicted to eaton Posted February 25, 2011 Report Share Posted February 25, 2011 it really shouldnt be warm to the touch, just enough to melt it. Quote Link to comment Share on other sites More sharing options...
AL Posted February 25, 2011 Report Share Posted February 25, 2011 They do get warm to the touch though... At least all mine do Quote Link to comment Share on other sites More sharing options...
88red4cyl Posted February 25, 2011 Author Report Share Posted February 25, 2011 Yeah, it doesn't melt anything at all, or even get rid of the fog.. Quote Link to comment Share on other sites More sharing options...
carkhz316 Posted February 25, 2011 Report Share Posted February 25, 2011 To add: the light will almost always light up as it gets power/ illumination independently; and as it just a command/ request to the BCM. There is (should be) a dedicated fuse and relay just for the power for the rear defrost. Quote Link to comment Share on other sites More sharing options...
W30post Posted March 5, 2011 Report Share Posted March 5, 2011 My 04 Monte Carlo has the connector pulled off the grid. The only thing that still defrosts is the driver's side mirror. I think the wiring routes through the driver's side mirror then to the back window and then the passenger's side mirror. This is just based on my cars operation with a disconnected grid:). Has anyone worked on the driver's door for any reason? Maybe they left something in there unplugged, if that is how this system really works.. Quote Link to comment Share on other sites More sharing options...
88red4cyl Posted December 14, 2011 Author Report Share Posted December 14, 2011 Bumping this old thread since I finally got around to fixing it today.. Which fuse is for the rear defrost? The only thing labeled rear defogger in either fuse box is a single relay.. Since thats something I'm apparently going to have to get from the dealer (auto zone says its a not available part in their system) I was hoping to try this fuse first. Quote Link to comment Share on other sites More sharing options...
rich_e777 Posted December 16, 2011 Report Share Posted December 16, 2011 I`m having the same issue in my 94 cutlass, sometimes the button wont engage the system and i cannot find the wiring diagram in the haynes book. Im sure its a fuse or relay but which one? Quote Link to comment Share on other sites More sharing options...
alec_b Posted December 16, 2011 Report Share Posted December 16, 2011 Do you have a meter available? If you do, put one the negative to ground and touch the positive to each line on the grid. You should have battery voltage on one end and close to 0 volts on the other. If you don't, you have a bad grid and the window needs repaired/replaced. I just went through this on a sable. The ground side of the grid had a bad connection at the window, and the meter would show 12v across the entire grid. Quote Link to comment Share on other sites More sharing options...
88red4cyl Posted December 16, 2011 Author Report Share Posted December 16, 2011 Do you have a meter available? If you do, put one the negative to ground and touch the positive to each line on the grid. You should have battery voltage on one end and close to 0 volts on the other. If you don't, you have a bad grid and the window needs repaired/replaced. I just went through this on a sable. The ground side of the grid had a bad connection at the window, and the meter would show 12v across the entire grid. I have no power to the grid whatsoever.. So either a fuse/relay is bad, or there's a break in the wiring somewhere... Since I can't find a fuse anywhere that is marked for the rear defog, I guess I'm just going to have to go to the GM dealer and see if they can get me the relay I need... Quote Link to comment Share on other sites More sharing options...
Addicted to eaton Posted December 17, 2011 Report Share Posted December 17, 2011 there is a fuse... if its not labeled then its like acc or something Check all the cabin fuses.. Quote Link to comment Share on other sites More sharing options...
Addicted to eaton Posted December 17, 2011 Report Share Posted December 17, 2011 The 40 amp BATT 3 fuse supplies power to the rear defroster through the defroster relay Quote Link to comment Share on other sites More sharing options...
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