just put a used lock assembly in a 2001 caravan for a customer. new ones are over $300 so we went the used one route. Well it all works except when he opens it with the switch it gets to where it should stop and the power door motor still is running and he said it jerks like its trying to open or shut more. Has anyone run across that before? He talked to a mechanic that looked up in some program that said it has to relearn itself on where it opens and stops at. When I ran it here at the shop it appeared to work correctly. Is there a sensor that tells the door when it should stop?

Thanks
corey