My grandmother's 1998 Caravan had been parked for about six months when she was unable to drive. Her van has a heated windshield and power locks, but no keyless entry, power seats or windows. The battery was left connected and at one point the doors began locking and unlocking themselves about once a minute. This continued until the battery went dead as my grandmother was unable to disconnect the battery. Somebody jump started the van and drove it to the dealer where it did not exhibit the problem. They happily charged her $100 and told her that they couldn't find a problem or fault code, but if it happened again they'd need to replace the body control module. ($1200 part, 1 hour labour) The dealer said that the power locks could not be disabled. The van made it two days without a problem and then began locking and unlocking again. I came out and disconnected the battery, but not before it was completely dead. We left it for a couple of months and purchased a new battery thinking that a weak battery would cause the lock malfunction. (this happened with my LeSabre) Everything was fine the next day and then it started again. We disconnected the battery immediately, left it disconnected overnight and then I connected it again. Sure enough, two days later it was locking and unlocking again. The locking/unlocking occurs whether the doors are left locked or unlocked, whether or not the automatic lock feature at 30km/h is turned on or off, and regardless of whether the van is being driven or sitting. It doesn't seem reasonable to spend the money to replace the body control module when the dealer isn't sure that's the issue - they said it was their best guess. She's ready to drive again, but can't be disconnecting the battery every time she parks.

Does anybody have ideas?
Can the power locks be disabled without disabling other components?
Is the body control module unique to the features of the car? (could it be replaced with one from a similar model, but that has power windows, for example)

Thanks,
Reid