I have a 2001 4.6 with power mirrors. I had to replace the driver side mirror. (I just bought the mirror, not the whole unit) After installing, I can no longer get either the driver of passenger side mirror to adjust. I checked the fuses, and they are fine. Did I perhaps not line something up right when installing the mirror? Why would it cause both mirrors to suddenly not work. (Had to replace mirror because it got broken by a baseball)

 

Still likely a fuse. Check fuse 110 in the under-hood fuse box.

If it's not a fuse, it's going to be something related to either the GEM module or the accessory delay relay.