Ford edge mirror

On our 2008 Edge awd I started noticing after I parked my car&then went back inside occasionally the mirrors(the glass part, not the entire mirror) would be pointed down which happened on both sides but not at the same time. If I recall correctly (this was a couple years ago)the control switch in the car wouldn't move it at first&I had to push with my hand on the mirror to adjust it again. When we took it to the dealer to have a new PTU seal put in under warranty (a year later a whole new unit) I believe they said it had something to do with the wiring inside the mirror. They seemed to have fixed it but it has happened since then but only once or twice. When we took the car for a test drive&I tested the mirrors (another salesman onlooking from on the lot said he had never seen anyone, even a mechanic, inspect&look over a car the way I did-I even brought my fridge magnet to check for hidden bondo!!) the switch moved the mirrors on both sides down&to one side but would not move it back up or the other side which I had them write up saying it would be repaired&that time it was the switch at fault. So I don't know if the 2 incidents were related or not. Have you checked to see if your mirror goes up by itself when you unlock the car inserting the key in the lock on the door? Good luck with your mirror dilemma. I hope I helped a little&if anything you know your not alone with this happening.