2013 GMC 2500 HD driver side tow mirror tilt up not working

[2013GMCSierra2500HD]

I just bought a used 2013 GMC 2500HD. As I was driving from the dealership I discovered that the tilt up direction on the driver side tow mirror would not work. All other directions (tilt down, left, right) work fine. What could cause this? The switch? The actuator / motor?

[davester]

Yes.  It could be the switch, could be wiring , could be a computer problem, could be the motor/gears in the mirror.

[2013GMCSierra2500HD]

I assumed it could be any one of these issues. What I’m looking for is suggestions as to which is the most likely problem investigate first source and if there are any online diagnostic and testing instructions to determine which of the many potential causes is the actual cause. 

[diyer2]

I would try this.

Remove the switch.

Remove the the wire harness from the switch.

Use a battery or battery charger for power.

Put power to the wire harness.

If all functions work switch is bad.

 

[2013GMCSierra2500HD]

Thx! Great minds think alike!  That's exactly what I was going to try first!