when i put my rear defogger on it last only a few minutes then turns off, it doesn't clear my glass and takes a long time before i can put it on again.

 

It is because the circuit breaker in the fuse panel is tripping. It seems like the defogger grid may increase in resistance over the years. You can try replacing the breaker or what seems to work for most people is to replace the 30 amp breaker with 30 amp fuse.
You can also make sure that the connectors to the window grid are clean and tight, so there is no added resistance there.

This question comes up annually when "defogger season" starts.

 

Wow I was having the same problem but I just learned to deal with it. I'll have to try that. Shoebox your the best.

 

i replaced the breaker with a fuse....WORKS FINE....i did this while back when someone asked about it... def worth doin ha

 

Yep, I asked this very question last year and the 30 amp fuse fixed the problem for me.

 

Same here.

 

Even though the fuse and the breaker are rated at the same amperage, the fuse seems to be able to tolerate the current without blowing. I replaced my breaker with a fuse years ago and it is still working. However, I did notice that the plastic shell of the fuse shows evidence of heat induced by the current. I am confident, though, that the fuse would blow before there might be damage to anything.

When you go to replace your breaker, be sure that you have not used the defogger for a little while. The breaker can get very hot and can burn your fingers when you grab it. It's not a bad idea to buy a pack of fuses and keep them in the car as a spare (or just keep your breaker handy). The breaker also serves cars equipped with power seats, so you might not want to be caught without a replacement (for those emergency "I gotta move my seat" situations ).

There have been a few people that have found dirty or partially broken terminals in the fuse box, too. Take a look at that when you have it opened up.

 

thanks SHOEBOX.

 

Mine is doing this also! I was going to test the resistance of the grid and try to trace the electrical to try to find the reason.
I should have just asked!!! I'll try the fuse.