2005 RX. Passenger side. Sometimes it works fine, other times I hear the motor try to turn, but nothing happens. When I hear the motor it's just a quick, dull thud sort of sound, not a continuous whine. It's like the motor tries to turn but something stops it. When it wasn't working for the first time, I took the panel off and removed the motor and it worked fine out of the door. Put it back and now it works ok most of the time, but sometimes I need to operate the switch a few time before it will work. I know it's not the switch though, because it acts the same with both the driver and passenger switches.

Since it seems like power gets to the motor, the only other thing I can think of is the regulator. The only reason I think it might not be, is because the few times I've had problems with a regulator in other cars, they made noise and would jam and generally work like crap. This is more of an either it works properly or it doesn't work at all sort of thing. Any ideas?