my driver side mirror stopped folding in. passeneger side still works great. so I bought a set of escalade mirrors on craigs list and the same thing is still happening! is there something electrical going on inside the door? Please help!

 

Common problem, do a search, they all break because of cheap gears

 

I had the same problem on my 09 Denali. Passenger side stopped folding, swapped mirror, still didn't fold. So yes, it's clearly an electrical issue.

I ended up switching to the HD towing mirrors, so I never investigated further.