Door Ajar message on my 2003 Eddie Bauer Explorer

[Motsiball]

I'm new to the forum. I just bought a 2003 Eddie Bauer Explorer and have a problem I hope you all can help me with. I keep getting a door ajar message on my dash with a beeping sound when driving. I've opened and shut all the doors to make sure they are properly closed but it does not fix the problem. The interior light will also turn off and on randomly whether the car is on or not. What makes it more annoying is that when I lock the doors the alarm sounds, thus forcing me to leave the car unlocked at all times. I could not find any door buttons against the door frame so can't figure out why it thinks a door is open. Any ideas on how I can fix this or if a code reader will tell me which door is the problem?

 

[xlt03]

http://www.youtube.com/watch?v=Vh2r7HrCMRs&feature=youtube_gdata_player
Go to YouTube and look for explorer door ajar problem.