The first thing to check would be the fuse. You can find this by looking in the owners manual for your car. It should tell you where the fuse box is and which particular fuse is for the rear defrost.
If that turns our to be the problem just replace the fuse, but if it blows again you most likely have bad wiring.
In my case the switch to the defogger was fried and had to be replaced. I would first determine where the problem is, then get a haynes manual and see how hard it might be to fix the problem yourself. If you can't do it then take it to the dealer.
Instructions on how to change the rear hub wheel bearings on a 1996 Chevy cavalier
Remove the rear speaker covers in your 1994 Chevy Cavalier. Remove the rear speaker retaining screws. Remove the wiring harness from the back of the rear speakers.
where is the rear defogger relay located in a Toyota Camry
Hi If it is the "track" across the rear screen type it can be repaired by using the silver 'paint' you can get from Radio Shack type stores. But do not switch it on for 24 Hrs after that you can give it another coat, then give it another 12 hrs.. best of luck .
front steering
Drum
No
It is located under the AC and Heat instrument panel
At the "Y" in the cables at the rear of the car
Over the rear axle
Rear of tranny