This is freaking me out ! Our 2002 Ford Explorer XLT V8 4wd is acting too weird and it does this intermitently. It has around 97K on it. The alarm sometimes goes on on it's own or it just stays off.
The automatic door locks sometimes work after you've driven a little ways or sometimes not at all or sometimes later in the trip. The door ajar light goes on and then back off and then back on again with the warning chime going off or stays off.

I hope you've experienced this before and can help.

Greg