This winter my drivers side mirror was turned off color I believe from the heating element, and I don't eaven know how to turn them off!

also can I replace just the glass?

 

Yes, the glass can be replaced separately.

On my '07 with cold package the heating element is activated automatically by low temps. I believe they will also switch if you push the button for rear window defog/deice element. The following information is available from your owner's manual.