Door ajar light stays on

Door ajar light stays on and interior light stays on with door shut how do I fix

I have a 2004 F150 King Cab Pick Up in pretty good condition. For some strange reason the cabin light won't go out when I get out of the pick up. I've checked several times to make sure the doors are all shut; the light switch. It has done this twice now: once in the day light when I first got in and then after I drove it back home. The first time the "door ajar" indicator was lit and I checked everything. Finally I decided to put it into reverse and the light went out. Then tonight after I returned home, it would not shut out and I'm certain the battery will be dead. What do I do?

You have a door latch that isn't working properly. You can use any scanner with data display to find out which door has the problem. Go to body control and you will see all doors. One of them will say open or ajar. These latches are fairly easy to change once the panel is removed.A temporary solution to your battery drain would be to disconnect the battery when your truck is going to be parked.