Door ajar light still on which leaves interior lights constantly

courtesy light switch , is door ajar switch an it's part of the door lock actuator . Light on coming on ? Not going off ? The ajar switch is a input to the GEM module , fords BCM - body control module . The GEM will energize a relay to turn on the lights .
The GEM will illuminate the interior lamps when any door is open or ajar. The interior lamps are; the dome lamp, the rear cargo lamp, the door courtesy lamp and the side rail lamps. The courtesy lamps will shut off when the doors are closed and the illuminated entry feature is not active or when the vehicle speed is greater than 5 mph (8 km/h). The interior lamps will not be reactivated until the vehicle speed is less than 3 mph (5 km/h) and a new door open warning lamp switch is received.
The GEM controls the interior lamps illuminated entry function by activating the interior lamp relay.
Mite be a good idea to have it check for DTC'S - diagnostic trouble codes .

B1322 Driver Door Ajar Circuit Short to Ground GEM GO to Pinpoint Test B . B1323 Door Ajar Lamp Circuit Failure GEM REFER to Section 413-01 . B1325 Door Ajar Lamp Circuit Short to Battery GEM REFER to Section 413-01 . B1330 Passenger Door Ajar Circuit Short to Ground GEM REFER to Section 417-02 . B1334 Decklid Ajar Rear Door Circuit Short to Ground GEM GO to Pinpoint Test C . B1338 Door Ajar RR Circuit Short to Ground

check the adjustment on the door switch it is the same one for the interior lights . or the switch is bad.

Bad door switch

look for a swich in the door fram itself .replace it and make sur its getting good contact to door jam

Most likely a door jab switch in a door,most likely the drivers door.

spray all door latches with a good penatrating oil spray alot in the laches slam the doors servral times thier is a switch in the latch that gets stuck it is replaceable but is hard to get at

If I am not mistaken, the plunger is located in the door with the latch. Most of the time you can just pull the door panel off and adjust the switch. After opening and closing the door, they get knocked out of adjustment. I sincerely hope that this helped you. Take care and best wishes.
Bryon

the wire on the door latch make sure they are plugged in or unplug it and the light should go out if it does not then it's not that door

It is a sticky sensor in the door latch mechanism. Spray it w/ WD-40 and follow up with a dose of silicone spray. Open/close doors several times and it should be ok. If you have a problem with 1 door the other 3 are sure to follow---DO THIS TO ALL 4 DOORS!!!!!!!!!

The switch that tells the computer that the door is closed is broken or has a loose wire.This causes the computer to think the door is open thus the door ajar and interior light on.Switch should be located on door jam.