For those of you without the display in the rearview, replacing the mirror with one from another vehicle is fairly simply. The higher end Genetex mirrors all have a 16pin connector. The connectors are fairly universal.
I have an onstar mirror that I'm replacing with an onstar mirror with temp and compass and auto-dimming. You will need to run wires for the temp sensor and also wires for 12V power. The 5V power and grounding is already pre-wired since I have onstar already.
Here is the standard Genetex wiring. Just unplug your current mirror's wiring harness to see what you would have to run in addition.
Pin 1-not used
2 - Microphone (if the mirror is equipped with it)
3 - "Passenger Air Bag
on" notification (if mirror is equipped with that display) - ground pin to activate icon
4 - "Passenger Air Bag
off" notification (if mirror is equipped with that display) - ground pin to activate icon
5 - auto day/night signal, which comes from the LH outside rearview mirror
6 - Temp probe connection ( if mirror is equipped with display)
7 - Temp probe connection (if mirror is equipped with display)
8 - Ground
9 - Ground
10 - Microphone (if mirror is equipped)
11- keypad signal (out) for On-star
12 - keypad supply (5v) voltage (in) for the buttons
13 - ignition voltage (12v -main power IN to the mirror)
14 - Green LED signal (to the right of the Emergency button) - apply 12v to light LED.
15 - Red LED signal (to the right of the Emergency button) - apply 12v to light LED.
16 - return line to the LH outside mirror for day/night signal