Had this problem since I got the car, just never bothered me since the mirrors were where I wanted them, but now I have let a few other trusted friends drive the car and they needed to adjust the mirrors and well, the passenger side would only move up and the drivers side would not move at all. I have already replaced the driver's side mirror assembly (when I bought the car it had what almost looked like rusty glass??), and I kinda doubt both mirror motors died at the same time.

I checked the fuse under the hood and tore down the door switch down to the board and cleaned off the board's contacts, neither seemed to work. Any ideas?

 

Try swapping the switch in the door

I tried cleaning one multiple times, and even though it looked fine, swapping the switch fixed the issue. Well, not until going through 3 of them... The first couple had similar issues with only some controls working lol

 

I got it working again. Pulled a used switch off a Jimmy in a scrap yard. Was happy when I saw both mirrors move all directions. Cost me $5.30 compared to that of $72 new (how the hell do they get $72???).