Side Mirrors not working

[RanjS8]

My passenger side mirror had stopped moving for over a year now....and recently it stopped folding....

So today I replaced the complete unit with another unit.

The only difference between the two units was that mine supported auto dimming mirrors, whereas the new unit did not....I think this was reflected by the fact that electric connector on the newer unit had fewer pins....

However after I replaced it....the new mirror was still not moving or folding....furthermore I noticed that the driver's side mirror was folding however the mirror was not moving.

Am I right in thinking that the above symptoms suggest that the mirror control unit is faulty or could it be something else.....