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rear defrost dont work...

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Old 11-10-2008, 04:03 PM
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Default rear defrost dont work...

Since I bought my car the rear defrost hasnt worked. I push the button but nothing happens... the light doesnt even light up, and from my understanding the switch clicks on/off, but it doesnt do that either. The seats work so its not the breaker. I tried swapping it out with the window breaker and nothing changed. So I can eliminate the breaker being blown. What else can I check to figure out why the rear defrost doesnt turn on?
Old 11-10-2008, 05:13 PM
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Was or is your rear window tinted? Maybe the person who removed tint or when he was putting it on fucked it up and cut the lines. Slim chance that ALL the lines don't work unless he used a razor blade right down the whole thing though. Check your defroster lines and make sure there not cut somewhere
Old 11-10-2008, 05:44 PM
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Not sure if this will help but good info: http://shbox.com/1/defogger_grid_test.jpg
Old 11-10-2008, 05:45 PM
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Originally Posted by fccs
Was or is your rear window tinted? Maybe the person who removed tint or when he was putting it on fucked it up and cut the lines. Slim chance that ALL the lines don't work unless he used a razor blade right down the whole thing though. Check your defroster lines and make sure there not cut somewhere
Damn, beat me too it. This is a big problem with tint shops, they just scrape everything off when they do the back window. Id go back to the tint shop and ask for the manager
Old 11-10-2008, 06:59 PM
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Originally Posted by udienow
Since I bought my car the rear defrost hasnt worked. I push the button but nothing happens... the light doesnt even light up, and from my understanding the switch clicks on/off, but it doesnt do that either. The seats work so its not the breaker. I tried swapping it out with the window breaker and nothing changed. So I can eliminate the breaker being blown. What else can I check to figure out why the rear defrost doesnt turn on?
If the switch doesn't light up or click, the switch is probably bad. Another one of those common faults with GM F-bods. Unfortunately the defog switch is part of the whole heat/air/cooling unit below the sound system. It's not hard to change but you have to replace the whole unit and you are looking at a couple hundred bucks or less just for the part. I think I paid $125 about 6years ago.

If you decide that is the problem, I can tell you how to change it. It's simple plug and play.
Old 11-10-2008, 10:27 PM
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my f-body didnt come with rear defrost lol. didnt like it at first, but after getting used to not having it, I really like it cause it looks cleaner.
Old 11-11-2008, 01:04 AM
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I was playing with my rear defrost this morning, and determined by trial and error that it works only under certain circumstances.

Water on the window = no
Frost on the window = yes
Window covered entirely with dew, just above freezing temp = no
Nothing on the window = no
Old 11-11-2008, 10:10 AM
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Originally Posted by fccs
Was or is your rear window tinted? Maybe the person who removed tint or when he was putting it on fucked it up and cut the lines. Slim chance that ALL the lines don't work unless he used a razor blade right down the whole thing though. Check your defroster lines and make sure there not cut somewhere
No, there is no tints on the car. I'll check the lines again but I dont recall seeing any cuts when I was trying to fix it the other day.


Originally Posted by ghardester
If the switch doesn't light up or click, the switch is probably bad. Another one of those common faults with GM F-bods. Unfortunately the defog switch is part of the whole heat/air/cooling unit below the sound system. It's not hard to change but you have to replace the whole unit and you are looking at a couple hundred bucks or less just for the part. I think I paid $125 about 6years ago.

If you decide that is the problem, I can tell you how to change it. It's simple plug and play.
Where did you buy this? Depending on price I might just leave it broken. Can't really justify spending money to fix something i bearly use. Car isnt used in winter so its even more reason to not wanna put money into fixing it.
I was hoping there was a common problem and easy fix that I didnt know about.
Old 11-11-2008, 07:20 PM
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I had this problem when I bought my car, the dealership fixed it for me. As was stated, if the switch is bad, which sounds like the problem, the whole HVAC unit must be replaced. Whoever figures out a way to fix just the switch should get some sort of prize. I wish I had asked for my old one so I could play around with it. I'll bet there is a way to fix it, with all the clever fixes for non-serviceable parts people on here have come up with, I think it could be done.
Old 11-11-2008, 09:35 PM
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Originally Posted by udienow
Where did you buy this? I was hoping there was a common problem and easy fix that I didnt know about.
I bought mine through the dealership. I"m not sure if it's available as an aftermarket part. It's a common problem alright. And you would hope that you could just replace the switch, but it is integral to the whole heating control unit.
Old 11-12-2008, 09:08 AM
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I guess what im trying to figure out is, what do I ask the dealer to get the right part? It's called the HVAC unit?




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