how do you know if your window heater works. i was warming up my car today and i tried the window heater for the first time and i didnt see anything different. my glass was still cold as ever and i dont see and tangable or physical changes or occurances.

 

Are you talking about the rear defroster?

If so, I think you can only tell if it's working if there's frost on the window.

 

maybe the mirror heaters?

 

I thought about that also. I guess the same would apply. The only way I know that they work (besides the switch lighting up) is to have frost (or ice) on the mirrors.