Installing Auto Dimming Mirror
 

Ive got a mirrior from a Bravada with no on-star and am going to put it in my 04 Blazer. Ive installed a mirror in my other car but I allready knew what I could tie into for Keyed power. I have the short Overhead console with sunroof and was wondering if anyone knew what wire I could tap into for power?

The attached diagram as well as the ones from THIS POST should help. If you have an auto-dimming mirror, you really should hook the backup wire up. It makes backing up into a well lit garage somewhat difficult if not properly connected. This is something that isn't as important on an SUV as it is on a car, but still worth mentioning.

For power, you can use the green wire at the DIC which is attached to the RDO_IGN fuse. The mirror shouldn't be enough to overload that circuit.