I have an Olds van and the doors sometimes act up. The doors not working properly seems to be a normal event for all vans. To this day, they still do not have all the bugs worked out. Have you disconnected the battery (change battery, repair on van, etc) or blew a fuse reciently? In most vans the doors have to be reset after such events for them to work properly. You can buy a repair manual from a parts store for the reset procedures.