Upgrading factory options

I recently changed instrument clusters to get a transmission temp gauge. All of the wiring and sensors were already in place, just the gauge was missing. So, my question is, what other doodads are all prepped and waiting for us to plug in the better component? I see heated exterior mirrors. Will the wiring harness from an unheated mirror work for them? Also, to upgrade to an interior mirror with temp and compass, is that wiring harness lurking above the headliner? And where would the temperature sender mount? Has anyone done either of these changes? What activates the heated mirrors?
Thanks, Tim

Hiya Powerwagon,

I am new to this site too....the only question of yours that I can answer is that the rear window defogger button activates the heated mirrors.

Barry

Thanks for that piece of the puzzle Barry. So, odds seem good that the wiring is there, if I added a rear window defogger button and heated mirrors, I might be in business. Anyone want to corroberate or debunk?

I'm not sure about the wiring being there....mine came from the factory already installed....