Because there is a problem with it.
its called the pu$$y
sounds like a bad door latch mechanism.
Beacause it is broken, most likely.
Fod product? Spray the door latch assembly liberally with WD-40, operate the door a few times then spray with a silicone spray
Connect the power and unlock the shut drivers door with your key.
Push all the door locks down manually and then lock the drivers door with your key if it will not stay locked when you push the lock down and shut the door.
make sure your door shims are not worn out,....open the door half way and lift the door up, if you feel slight movement or looseness in the door you may have to replace the shims
a door in your car is not fully shut.
dd
Get a new car you loser.
If the door is shut then it's probably the switch in that door or wiring to it.
Why do interior lights stay on when engine is shut off on 2001 Lincoln Continental car?