Dome light stays on when it is very hot outside and during a sunny day. The door ajar light on instrument panel lights up also. Both stay lit until it cools down or the sun goes down.

It can be issue with faulty sensor or a wiring issue.Troubleshooting is required.
Click the help link shown below:---
Door Ajar Light and Dome Light Remains ON? http://whoisbyme.blogspot.in/2012/06/2003-mercury-sable-door-ajar-light-and.html
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Door ajar light stays on? http://technoanswers.blogspot.com/2012/01/door-ajar-light-stays-on.html

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Thanks.

I have a 2000 and the side door has four prongs sticking out of it, they are spring loaded. when mine messed up it was for the speakers. I took mine apart and fixed it, A spring had popped out some how. They are a simple setup.

the door adjar switch is the problem. the cargo light stays on until 35mph, as well as the overhead dome light. i just took the bulb out of the dome light and dont worry about the cargo light. it stays on for 30 min after the truck is turned off if the switch didnt trip properly. it shouldnt cause any problems as long as your batteries are good. i havent replaced the switch yet but it should be on the part of the door by the latch. get the replacement part and do a visual I.D. when you get the panel off. then replace it. the sensor is only 14$

i must say that i feel your pain with this,, my door ajar light does the same thing but my dome light doesn't come on when the doors are open, i have to flick the switch on the dome light to make it come on. In my opion and i stress my opion it saounds like a issue with the body controller, im not sure what ford calls it but it controls all the body functions, i dont think the low coolant light is connected to the body contoller but i dont know this for sure, i think that light is controlled bny the engine ecm. some times a dealer can connect to the body controller and see if there are any fault codes for circuits that it controls and or monitors, also they can reflash or update the configeration and or calibration level cause ford release's fixes for issues all the time, same theory works for any control module on a vehicle. i dont think any of the auto parts stores have the right program to connect to bofy controlers but i could be wrong, worth looking into. i only put up with mine cause i use it as a beater, if you are worried about your dome light staying on and drianing your battery then you could pull out or disconnect the dome lights for the time being, its not a fix but just a band-aid.

There is a switch that connects to the door latch inside the door. They can get sticky or come loose causing your complaint. Usually it is the drivers door since that door gets used the most. The door panel has to come off to access the switch. Sometimes you can remove the dome light fuse to take care of the light and indicator until it gets repaired.

To temporarily solve the light problem, I taped a washer to the inside of the door where the door hits the plunger on the light switch. A permanent solution would be to drill a hole in the door at this spot and put a self taping screw in that will trigger the switch sooner. I figured out the reason the dome light stayed on is due to the courtesy light timer and the lights would have eventually gone off.

Don't think you have a door ajar switch problem , more then like the lighting control module is the culprit . Does the door ajar light on the instrument cluster stay lit ?
The interior lighting can be separated into two distinct modes of operation: the courtesy lighting and the demand lighting. The lighting control module (LCM) controls all of the interior lighting in the vehicle, as described in the following text.
The front dome lamps, rear reading lamps, and instrument panel courtesy lamps, can be illuminated either by opening any of the vehicle doors (courtesy lamp function) or by depressing the headlamp switch (demand lamp function).
When any door is open, the door ajar switch grounds an input to the LCM which then sends power to the courtesy lamps. The voltage sent to the courtesy lamps gradually increases from 0 volts to 12 volts within 500 ms (± 50 ms), to achieve the theater lighting effect. When the door(s) are closed the door ajar switch(es) break(s) the ground to the LCM input which then gradually reduces the power from 12 volts to 0 volts within 5 seconds. (± .5 second).
When the headlamp switch is depressed it grounds an input to the LCM which in turn sends 12 volts to the front dome lamps, rear reading lamps, and instrument panel courtesy lamps. When the headlamp switch is depressed a second time, it breaks the ground to the LCM input which then ceases to send power to the front dome lamps, rear reading lamps, and instrument panel courtesy lamps.

The battery saver will disrupt power to the courtesy lamps after 10 minutes, the demand lamps after 30 minutes, and the headlamps after 10 minutes. Turning the ignition switch to the RUN or ACC position will terminate the battery saver feature by disabling the interrupt timers and reinstate power to the lamps.
Do you know what DTC'S are ? diagnostic trouble codes !
LCM Diagnostic Trouble Code (DTC) Index DTC Description Source Action B1322 Driver Door Ajar Circuit Short to Ground LCM Go To Pinpoint Test F . B1442 Door Handle Switch Circuit Failure LCM Go To Pinpoint Test G . B1445 Door Handle Switch Circuit Short to Ground LCM Go To Pinpoint Test G . B1563 Door Ajar Circuit Failure LCM Go To Pinpoint Test C . B1566 Door Ajar Circuit Short to Ground LCM Go To Pinpoint Test H . B1685 Lamp Dome Input Circuit Failure LCM Go To Pinpoint Test I . B1687 Lamp Dome Input Circuit Short to Battery LCM Go To Pinpoint Test I . - All Other DTCs LCM REFER to Section 419-10 .

PINPOINT TEST C: THE COURTESY LAMPS STAY ON CONTINUOUSLY CONDITIONS DETAILS/RESULTS/ACTIONS C1 CHECK THE SYSTEM OPERATION Open and close each door, making sure that each door is completely closed.

• Are the courtesy lamps still illuminated after the 25 second time-out period?

Yes GO to C2 .

No The system is operating correctly. C2 TEST DOME LAMP SWITCH Depress the dome lamp switch.

• Are the courtesy lamps still illuminated?

Yes DEPRESS the dome lamp switch a second time. GO to C3 .

No The system is operating correctly. C3 CHECK THE LIGHTING CONTROL MODULE
LCM C2145a

• Are the courtesy lamps still illuminated?

Yes REPAIR circuit 53 (BK/LB). REPEAT the self-test. CLEAR the DTCs.

No INSTALL a new LCM. REFER to Section 419-10 . REPEAT the self-test. CLEAR the DTCs.

Its the problem with door switch on the car ,you need to replace the switch
open the car door and you will find button shaped switch on the door frame ,you need to replace it ....

Good luck...

have you had the door panel apart before for anything, the switch is on your latch inside your door. I hope this helps you. I am just trying to be helpful, and will help you all the way through your repair if you like, My compensation is my rating. please be generous..lol

This is usually caused by the switches sticking in the door latches. Try spraying some WD40 in the latches and open and close the doors a bunch of times that should take care of it.