As long as the motor spins, the motor should be working.
When I first got my TTA I has headlight problems also. At first they would go up but they would not go down, so I replaced the switch and that cured that problem
So time went by and the passanger side one would go half way up and not fully extend, I heard the motor spinning, so I knew it was not the motor.
By design the headlight motor assy. has pellets in it that wear out over time, so they need replacing.
So I got the deluxe headlight repair kit from topdownsolutions.com, it came with the instructions and everything you need to rebuild both headlight motor assemblys..
I only rebuilt the passanger side, and that was the only one I needed done. Follow the instructions and it was a relative easy task. If you got a problem you can always e-mail Lon at topdownsolutions.com.
This is what was wrong with mine and it maybe the same with yours, those pellets that extend and bring the buckets back down do wear out.