I bumped the passenger side mirror on my f150 on a tree branch (causing it to fold forward, but not breaking the glass) as I was backing it into the canvas pavillion/garage-thing where we keep it. I was able to fold it back into place (the side mirrors are apparently designed to fold in).

Ever since then, that power mirror doesn't move in any direction when I use the switch. However, the driver side mirror still adjusts just fine.

So, what's the troubleshooting procedure to find out where the problem is?

The Chilton book is no help, that just says how to remove/install it. My web searches just turned up results about fixing cause xyz, but nothing about how to track down the cause.

 

Sounds like an issue with the mirror head, considering it got hit.

Remove door panel to expose the mirror connector.

2 routes

1. Apply power directly to the wires for the motor direction and see if it moves.

eg : + VDC on the violet wire and ground on the yellow wire will move the mirror glass up or down. Reverse the wires, and the glass will move the other direction.

2. Use a meter to test the connector from the truck. If the power is at the wires ( eg violet and yellow ) that points at the mirror head is the problem.

Considering what you did, it is a 85% sure case that the mirror head is damaged somehow.

 

Thanks. I was hoping against reason that it would just be a loose connection I could repair, but I'll have to dig in there and find out. Thankfully it was already set at the ideal angle so it's not a very urgent problem.

 

It very well could be a connector that got pulled apart, but you won't know until you pull the mirror head.
- BTW : If the Chilton directions for removing the head don't do it for you, download the Muth Co signal mirror directions. These are pretty good for directions on how to remove the door panel and mirror head, even removing the glass from the mirror head itself.

If you need to adjust the mirror in the short term, you can just push on the mirror to move it. The teeth on the plastic "drive shaft" will just ratchet on the motor.

Makes a nasty sound, but it will work.

This is the same sound you will hear if the mirror is full in one direction and the motor keeps trying to move it in the same direction.