explorer door ajar aggravation

[colonyofdrones]

So I've been looking around the net for this and the discussions that I've seen so far have led nowhere or the circumstances aren't the same as mine.

I'm working on a 2004 Explorer XLT 4WD

At some point a couple months ago it began showing a "door ajar" light on the cluster even when all the doors are closed. Come to find out it can be ignored by turning the interior light dimmer switch all the way down. Otherwise, the dome and puddle lights stay on even when all of the doors are closed.

First, I tried WD40 on the lock assemblies in all of the doors and hatch and it made no difference in the symptoms.

Second, I used AE to find out which door was setting the ajar light (drivers door) and replaced the sensor inside the door. This also made no difference in the symptoms.

One thing I find interesting is if you have the dimmer switch all the way down to where it clicks and turns off all interior lighting, the door ajar light works as expected. You open the door and it comes on and when the door is closed, it turns off. However, if you click on the dimmer switch to where the interior lights are on, the door ajar light will be off until you open any of the doors and then when closed, the ajar light stays on until you turn the dimmer switch off again.

I've heard of people throwing various parts at this problem, but I'd rather be able to understand whats causing it instead of blindly wasting money. Perhaps someone here will have also been through this issue and knows of a possible solution.