Headlight goes up. Won't go back down., What is broken here? Options

[VegasRacer]

Both headlights pop up as the German engineers intended. Only the left one returns to the down position with the dashboard knob. The right one will go down using the knob on be back of the motor.
What is causing this malfunction? (IMG:style_emoticons/default/confused24.gif)
There are no obstructions. The usual suspect pivot is intact.
Is this a sign the headlight motor is going bad?

[GeorgeKopf]

This is the gear mechanism with the conductive plate. You can see the three tracks that the pickups ride on.


Here is a close up of the conducive plate. Notice the white plastic spaces on the inside and outside. This is where the motor stop moving in one direction.


Here is a close up of the three pickups.


BTW: I have six old headlight motors (3 for each side) and only one of them works. I took four of them apart and they are different in their construction. The electric internals, the shape of the screw gear and the external connectors are different. Not sure if this is "older" vs. "newer" versions but they have the same part numbers.

George