Power door lock mystery
 

Alright I have a weird ( or maybe not so weird) issue with my driver side door lock. When the car is running it works fine. However when I turn the car off the lock gets" locked" up. It won't go up or down with the switch or manually pushing it down. It's like it's jammed. The passenger door is fine lock works all the time, it's the drivers door that doesn't work.
I'm just confused why it works when the power is on but then when off it's impossible to lock even when pushing down on it. It goes about half way down then that's it and it comes back up.
Would like suggestions since I work in a ghetto area and don't want it getting broken into haha. Thanks.