heated mirror

So this past week at the dealership I finally found out why my driver side heated mirror is not working. Last year in January had my car at the dealership and included in the list of work was diagnosing why my driver side heated mirror was out along with my rear window defroster only having the...

2003 Trailblazer: When I turn on the rear defroster, my front passenger side window and door lock buttons blink and click on and off every other second. If you try to put the passenger window up/down from the drivers side or the passenger side while the rear defroster is on and the button is...

My '02 Envoy has heated outside rear view mirrors, however the drivers side is NOT working. Anyone know why ? Could it be loose wires ? A seperate fuse ? Any help would be appreciated.