you may have a circuit or you can check your doors for any malfunctions
Is door ajar light on also?
On my 2002 sportage 2-door, the door ajar light stays on when the tailgate is not locked. with the key.
If the door is ajar and light stays on, spray some WD40 into the latch. The door switch is probably stuck. Spray all doors then open and close a few times.
If the lights are on and the door is ajar it will make a steady alarm.
change blown fuse for interior light,fuse is found on the inside drivers side kick panel....
Try spraying WD-40 on the door latch, the part that is on the door itself. The door ajar switch is located in with the latch. Had the same problem, door ajar light on, interior light stays on, and horns toots twice when you lock with remote, to signal door is not closed. Door was shut but truck didn't know it, WD40 fixed it.
bad door ajar switch inside one of the doors its in the striker assy
check the sensor on the door, its probably bad
you need to check your fuses first ( sounds like it) they are on underdash (drivers side)
Because one of your door sensors are broken.
Just spray some wd40 in all the latches. The sensors are in those latches. I had the same problem and it solved it for me
Check if the fuse for your interior lights isn't blown. On many cars the Door Ajar light will come on when there's no power to the interior lights. The dashlight then grounds itself through the interior lights. It depends on the car made. for example Taurus, just lubricate(real good) the lock with wd40, will take care of the problem. some cars have sensors will lock automatically when you close door then will LOCK automatically. if one of the locks is jamed the ajar warning come on. Easiest way lubricate all doors lock you will fine. Good luck