I found quite a few similar threads and no really good answers. My mirror only tilts vertically and does not move horizontally (left to right). The passenger side mirror works find so, I guess its not the switch. Do I need a new motor? If so, where might one look for this?

 

Try L-tunedparts.com. Talk to Steve Ganz. Motor is no good. You can only get the whole mirror assembly, not just the mirror motor.Good luck.
Will