does anyone know how the heater actuators work? are they similar to the switches that would be on the window system where any resistance and the motor stops? ive taken 2 heater actuator (motors) of, and the small piece of plastic that's on both that turns the outside cogs has snapped of flush with the side of the motor leaving a bit in the motor casing. was wanting to know if these actually stop the motor when it turns to its final position. one of the motors runs constantly until this small piece of plastic catches as it spins round. so I don't know if ive got a faulty actuator motor, turning and then braking this plastic or it stops with this pressure from the plastic and this is the correct way it is. very hard to explain what im on about, any comments on this would be helpful. ta