Its that time of year when I need to use the rear window defogger, however, after pressing the button it only stays on for a short time. Sometimes less than a minute. Last year it was staying on for ages after I pressed the button and was getting the job done.

I only have a shortish drive every day, and as its not all getting cleared it builds up between the metal lines and gets pretty heavy until I get in there and physically wipe it off.

Whats causing the system to switch off so quickly? I thought it was supposed to stay on for about 5 minutes at a time?

 

It should stay on for 10 minuted on the first push. The breaker may have gotton weak and replacing it might help, but you can also replace it with a 30 amp fuse and that may solve your problem It has worked for me for years. Just keep a spare or two handy just in case.

 

is the breaker part of the switch itself? Or is it some where else in the circut? I'v been having the same problem with mine for a few years now and couldn't never figure out what was wrong with it.

 

It's in the dash fuse box.. [breaker looks like a silver box ] and you just take it out, and put in a 30 amp fuse.

 

This has become a very common problem on late-model 4th-gens. My car suffered this a couple years ago (under warranty) and the dealership's fix was to replace the entire back glass! Their claim was that the resistance across the heating grid was too high (or low? ) and drawing too much current, thus overheating the circuit and tripping the breaker, which also supplies power to your power seat controls.

Initially they replaced the 30A breaker with a new one, then my defroster was working OK again, but they still changed the glass. I'd try the 30A FUSE "trick" first, and likely you won't have any problems with it. A lot of other guys have done that and AFAIK, their cars haven't caught fire yet!

 

Thanks for your replies, I'll give the fuse idea a try.

But am I right in saying that if I swap the breaker out for a 30 amp fuse, when I press the defogger button it will stay on until I manually turn it off?

If so, if I forgot to switch it off, would switching the ignition off reset the circuit until I next press the button when the ignition is on again?

 

It will go off by itself, just like the breaker.

 

There is a timer in the switch. 10 minutes on the first push. If it times out, the second time you push it, it will stay on for 5 minutes. It won't operate any different with the fuse or the breaker.

 

thats what I though, but I'm still gonna try the fuse trick thing and see what that gets me.

 

I have been using the 30A fuse for years now with no problems whatsoever. You will be happy when your rear defogger actually defrosts properly again!

Jeff