Rear defogger/defroster problems
Thread Starter
Joined: Oct 2004
Posts: 2,142
Likes: 9
From: South Windsor, CT
Rear defogger/defroster problems I have a problem with my rear defrost turning off prematurely (like...after 45 seconds).
I've searched, found many threads like this one https://ls1tech.com/forums/stereo-el...er-switch.html and tried both a new 30 amp self resetting breaker, and a 30 amp fuse. The fuse blew after about a minute, and the breaker goes into a cycle of off and on...it's actually kinda funny with the breaker, as it resets, the defogger comes back on, then off and on and off.
So I unclipped the wiring from the rear window and checked with a multimeter, no short to ground at all, the rear glass has been replaced this year as well (had a scratch on it that wasn't buffing out very well) which had no effect on it.
So at that point, I called a parts guy who is a friend of mine, and he got me a new HVAC control for $85 new from GM...I guess some other dealer was going out of business and had it in their inventory at a big % off cost...that didn't fix it either...which bugged me because it was $85...but on the other hand, it looks brand new too (I never thought the old one looked old until I saw the new one...I guess just being 9 years old made it look old)...so whatever, I don't consider it an entire waste of money...but at this point...what else is there that could be wrong?
I'm about to head outside and take the breaker out, and put an ammeter across the lugs in the fuse panel and turn the defrost on and see how much current everything is really drawing...
If anyone has any ideas, I'd really appreciate it. I live in MA, and the snowy season just started...it'd be nice to be able to use the defrost successfully when driving to work like I was able to do a year ago.
I've searched, found many threads like this one https://ls1tech.com/forums/stereo-el...er-switch.html and tried both a new 30 amp self resetting breaker, and a 30 amp fuse. The fuse blew after about a minute, and the breaker goes into a cycle of off and on...it's actually kinda funny with the breaker, as it resets, the defogger comes back on, then off and on and off.
So I unclipped the wiring from the rear window and checked with a multimeter, no short to ground at all, the rear glass has been replaced this year as well (had a scratch on it that wasn't buffing out very well) which had no effect on it.
So at that point, I called a parts guy who is a friend of mine, and he got me a new HVAC control for $85 new from GM...I guess some other dealer was going out of business and had it in their inventory at a big % off cost...that didn't fix it either...which bugged me because it was $85...but on the other hand, it looks brand new too (I never thought the old one looked old until I saw the new one...I guess just being 9 years old made it look old)...so whatever, I don't consider it an entire waste of money...but at this point...what else is there that could be wrong?
I'm about to head outside and take the breaker out, and put an ammeter across the lugs in the fuse panel and turn the defrost on and see how much current everything is really drawing...
If anyone has any ideas, I'd really appreciate it. I live in MA, and the snowy season just started...it'd be nice to be able to use the defrost successfully when driving to work like I was able to do a year ago.
Thread Starter
Joined: Oct 2004
Posts: 2,142
Likes: 9
From: South Windsor, CT
Nevermind...can't go outside with the multimeter...at least the one I have is a 20 amp max meter, so rather than damage it, I guess I'll dig through the factory service manual and see if I am missing something.
Hmmm...I replaced my breaker with a 30A fuse and all's been well...you didn't try to move the power seat at the same time as the defroster was on did you? From what I understand, if you replace the breaker with a 30A fuse and have the defroster on and move the power seat, then that will cause it to blow.
Thread Starter
Joined: Oct 2004
Posts: 2,142
Likes: 9
From: South Windsor, CT
no...I am tall, my seat is all the way down, and all the way back, and I never move it...I haven't moved my seat in 2 years since I got the car and put it where it is.
