Hey all,
First I need to explain that this does not pertain to an F150, it's about my '05 Merc Mountaineer. I'm not a member of any forum for Mountaineers, but I've been coming here for years and I trust the judgment of the users here for probably any Ford-related question. My Mountaineer has got a constant "door ajar" message, meaning it thinks there's always a door open. What that means is, if ignored, it will leave the interior lights on til the battery dies. We figured out that you can completely shut the lights down by dialing the dimmer adjustment dial til it clicks "off". But that means that at night when you get in the truck it is completely dark and the dash lights are out until you re-adjust the dial. It's just aggravating. I don't even see switches in the doors to indicate the status of any door to say it's open. How does it know, and how do I go about finding the source of my issue? I know we're going to forget to turn the dial off, and come out to a dead battery, and it's always possible in the cold weather that the battery may not be recoverable even with a charge. Is this a common problem, so that maybe it won't take much troubleshooting to fix it? Thanks for your understanding and help.

 

I think most Fords are in the latch mechanism in the door jam where the door shuts. there are several YouTube for various vehicles.

Most say the latch sticks so maybe some graphite lube might be worth a try before replacing the entire switch.