When you start the car the window defroster is on. It stays on and works. If you push the switch it doesn't shut off. Eventually during longer drives it will turn it's self off but then I can't turn it back on. Any ideas? I checked the switch and I think it works the right way.

 

Are you referring to the rear window defroster? What year is your car? These cars have a timer on the switch/system. I think it will run for 15 minutes and cut itself off.

 

Yeah I understand that but why dose it turn on with out me turning it on? Why can I not turn it off. Why after it's turned it's self off I can't turn it back on? I have tested the switch

 

Yes it is the rear window defrost.