02 envoy mirror temperature sensor

my 02 envoy temperature sensor display (inside the rear view mirror) stopped working (always said same temperature)..

So i asked the dealer to fix it.. their response was to change the entire mirror at a cost of 744$CAD..

But it now just says 0 degrees and doesn't change.. This kinda leads me to believe that perhaps the mirror wasn't the problem and the old mirror was just displaying the last temperature it got from a sensor before the sensor died/ unplugged or something?

If that's the case I want my money back/old mirror back and get the real source of the problem corrected..

Thoughts?

The sensors on the "gentex" auto dimming/compass/outside temp mirrors do go bad... The sensor itself can usually be replaced free of charge if you call Gentex direct. The will mail it to you and the sensor is located up in the front bumper assembly.
If the mirror itself "was" in fact bad (which rarely is the case), you could always go on E-Bay and get it. If you paid anything over $30 for it ebay or not, you should get your oxygen levels and head checked. These items are a "dime a dozen".
Dont go to the dealer for the part, if you do I will personally drive to Canada ( I live in Metro Detroit michigan, Canada is 15 minutes from me) and personally smack you upside the head. If you need help email me, I will gladly help you to save you a few bucks.