Labeling and testing junk yard Gentex mirrors. The one with the compass is the 453. The non - mirror is the 313. Both use 3 wires to function, ground, hot for the homelink (garage door buttons), and hot for the auto dimming and compass of you have it.

Super easy to identify. Now you just need to figure out how you want to wire it up in your car. Tap a fuse are easy if you want to run it from your interior fuse box. If you have accessory lights or sun roof controls on your headliner, you may be able to identify ground and hots there also.

Install at your own risk.