02 XLT Explorer Door Lock Issue
 

I have an issue with the driver side door lock. With the door open I can lock and unlock it with the car on. when I shut it off I can not. I can if I turn the dimmer switch all the way off. Pretty weird, also when I shut it off the radio goes out and lights come on, almost as if when I open the door but all the doors are shut and no door adjar light on. Even more weird. Any suggestions? I dont want the battery to die if I forget to shut the dimmer switch to off at night.

sounds like the door switch, located inside the door panel.

It might also have an aftermarket keyless/remote anti theft system. Are you the original owner of the vehicle, and did this just start?