My rear defrost has never worked since I got the car and now I am trying to get it to work but can't figure it out. I get now power from the drivers side connector grounding it to the car body, so I am assuming that my problem lies before it even hits the rear window. I pulled the switch out and made sure the connector was on good, but when i push on the switch the light doesn't come on or anything at all. I checked the wires in the back, and one is hot 12V and one is ground, but the other wires didn't do anything... so I am stuck, i really have no idea how it works and need some help.

 

He he he. Get a louver, the frost will stay off the back window.

 

try replacing the Switch assembly, you can snag it at the junkyard for liek 5 bucks, i had to replace mine and it ended up working fine!