Since I never received any reply, I thought I post update on my van. My first mechanic gave up after replacing three alterntors. I had him put ford alternator but the problem remain. The other day while driving the lock/unlock noise start coming. I took the van to another mechanic. Evidently, he had a Windstar 2002 SEL (like mine) with exactly the same problem with the alternator... what are the odds! To cut the story short, he has isolated the problem to the computer. He is replacing the computer on the other van and will test on mine if that will fix the problem. Its been frustrating few weeks.
Arif | 
