Rear defroster not working

[rob101]

my car has had dew on the rear windshield for the past 2 mornings on the way to work. So I turn on the rear the rear defroser the button LED illuminates but the defroster is not working at all!
I turned it on for 40 minutes turning it on again when it switched itself off but when i touched the rear windshield it it was cold. I have read there is a relay and fuse under the rear seat, I am confused that the switch LED came on though. Are these likely to be the only things that i should check?

[pgrindstaff]

I've had this problem in the past. If you look in the fuse box under your back seat you'll find that one of those fuses is for the defroster. I believe there is also a relay that you will hear when you press the button to turn on the defroster. I found it quite strange that the light in the defroster button came on even though the fuse had blown but I guess everything can't make sense. I can't remember the fuse number off the top of my head but its one of the green ones. Hope this helps.

-patrick

[rob101]

I've had this problem in the past. If you look in the fuse box under your back seat you'll find that one of those fuses is for the defroster. I believe there is also a relay that you will hear when you press the button to turn on the defroster. I found it quite strange that the light in the defroster button came on even though the fuse had blown but I guess everything can't make sense. I can't remember the fuse number off the top of my head but its one of the green ones. Hope this helps.

-patrick
thanks mate, I guess because its a relay the fuse under the hood is for the control side and so is the LED ie the side which switches the relay, whereas the other fuse must be for the power supply which is controlled by the relay. that just occurred to me. I will have a look, which side of under the back seat is the fuse box?

[BillionPa]

the problem i had was the defroster relay would switch on and off 3 times a second till it fried. bad climate control unit responsible

[pgrindstaff]

thanks mate, I guess because its a relay the fuse under the hood is for the control side and so is the LED ie the side which switches the relay, whereas the other fuse must be for the power supply which is controlled by the relay. that just occurred to me. I will have a look, which side of under the back seat is the fuse box?

The fusebox in my car is under the left hand side of the seat, the battery is on the right hand. Not sure how it is in your car but it should be similar. Most of the fuses will be hidden buy a cover that you have to unscrew to access the fuses.

[632 Regal]

mines always on, no LED or anything, can fry eggs in the summer...no probs so far. Children learn not to touch glass in my car real fast.

the problem i had was the defroster relay would switch on and off 3 times a second till it fried. bad climate control unit responsible

[LunatiC]

Hey Rob,

I had this exact problem about a year ago, LED on the switch will turn on but the rear window stays icy cold. My problem was just a burned out fuse (it actually melted and fused with the plastic wire holder), and it is located under the rear seat on the passenger side (RHD).

I didn't test any relays after I replaced the fuse, I just saw a burned out fuse and replaced it and all is good ever since. Good thing too, if the fuse blew out again shortly after then I know I have an auto-electrical problem, which isn't fun to diagnose and repair.