Something odd is going on with my sunroof and I can't figure it out. The sunroof won't open, so I checked the voltage at the harness and I'm getting +12 and -12 when operating the sunroof switch.
So I figured it was the motor and found another one, and it still didn't work. I then had a friend attach the new motor up to his harness in his car and the motor spins fine.

If I just let the motor hang from the ceiling it doesn't even click or move when the switch is operated, and if attached (bolted in position) it does not do anything either.

So the motor is known good, and it's getting voltage. What's going on?
Thanks