Lubricating each door switch has not work to fix the “door ajar” issue on a 2003 Ford Expedition EB model. I have traced both front door wires to a single harness plug, but have not been able to find a pin-out description. Does anybody know where on the wire harness each door ajar switch can be tested?
Wow, what a royal PITA! Ford apparently did NOT have a better idea when it comes to their implementation of the pin switch: http://www.expeditionforum.com/f41/ford-door-jamb-switch-replacement-22003/
I’m willing to bet that if you ask the parts window guy at your local Ford dealer for a copy of the schematic and/or wiring diagram he’d print it/them for you…
By the time you check each switch it might be faster and easier to just have a shop tell you which door switch is malfunctioning. A scan tool will tell you in a couple of minutes. If someone asked me to do this I’d charge about $50 to hook up and check the switches.
You can diagnose this yourself. I would bet that with the key on, when a door is opened, there is a tone. Whichever one doesn’t emit a tone when opened is most likely the offender. Remember, with the key on.
If it’s a door ajar issue I’m guessing one of the switches is failed causing it to alarm continuously. That would be far more aggravating and difficult to isolate than one that failed to indicate when it was open…
Couldn’t OP just look at the dome light while opening and closing each door one by one? If the dome light doesn’t come on when the door is open, that’s the bad switch.
Edit: If it is saying the door is open when it shouldn’t, but intermittently and rarely, close all the doors. The dome light should be off. If it is, push on each door one by one and see if the dome light ever flickers on.
I’ve had them take more than one application of CRC’s Electro cleaner. I usually do it by spraying and then holding the outside door handle open, while actuating the door latch a few dozen times with a screwdriver.
If the Expedition is anything like my Lincoln sorting things like this out can become frustrating due to the complexity.
My Lincoln has the normal door jam switch but also has 2 switches in each door handle assembly along with a keypad and dome light operation is not based completely on the door jam switch.
The Helm manual on my Lincoln devotes 4 full pages of wiring schematics to the courtesy lamps alone.
The KISS rule was not considered during the design phase… 
I don’t think Lincoln owners make that particular purchase b/c they want a simple automobile design that is easy to debug.
Look at the contacts and or switch, then look at the wires between the door and the frame, they are the most common points of failure.
Great suggestions! I found the offending switch by opening doors after the timer turned the interior lights off. And yes, it was the last door of five. Each working switch will activate the interior lights, only the bad switch would not, since it was already “ajar”. Over a 2 hour period, I opened and closed each door until I found one that did not turn on the lights.
Brilliant! Good thinking. I certainly hope you are as good a medical diagnostician as you are with cars. Say, you don’t live in the McAllen area, do you? 
Great tip. However on my 2004 Expedition, that test indicates that both driver side doors are at fault, i.e., neither driver’s side doors light the interior lights after it has timed out, whereas both passenger side doors do. In addition, the window on the rear driver’s side is dead.
Does this mean I have 2 bad switches, or is there a common ground line for those two doors that is likely broken? Anyone know how these are wired up?