Originally Posted by Richbot
I'm wondering if this is a mechanical or electrical failure on these things when they drop out at less than 1,000 miles and greater than 60,000 miles or sometimes never? Seems like a mechanical design defect would be more consistent a'la E36 water pump impellers at 60-75k
I would think it is most likely an electrical issue with the motor....... i.e. increased internal resistance. If there is little damage to the gears the only other thing that could cause an issue is that a bushing on one of the gears may be getting tight or something.
Disassembling a new versus failed actuator and testing the motor for resistance or the gearbox for additional drag would allow you to pinpoint the problem. There is a possibility it could be an issue with the circuit board as well, but generally speaking solid state electronics are pretty reliable unless damaged by moisture!