headlight motor problems

[TurboTuli]

I installed the headlight motors I yanked from a junkyard yesterday. The problem is they will only make the headlights go down. I have to manually twist the knobs to make the headlights go up, and then if i want them down I press the switch. But if i press it again, they won't go up. And I have to make sure to press the switch again before manually twisting the knobs, otherwise I meet some resistance...like its trying to move, but won't. Its kind of hard to explain. Any idea what might be causing this?