Chrysler Repair: 98 minivan: Power door locks possesed, dodge grand caravan, power door locks

Question
Roland,  I have the problem above on a 1998 Dodge Grand caravan 3.3L eng with Remote Key Entry. The problem (I think started) after I replaced the van battery.  The battery was being replaced because it seem to be week when turning over the engine.  After sitting over night the battery would read 10.8vdc.  I installed another battery (same size #34) that I had.  The van started okay and the next day was reading ~12vdc.  But it seemed that after I did that the electric locks would try to lock (if key was not in ign.)every 30-35 seconds, while just sitting there not running. I am now wondering if this may have been happening before I change out the battery and may have been what was draining the battery. {Note: van used by my daughter and was at college with her before she brought home to check out the start problem}.  In an effort to track down the problem I tried first disconnecting the battery again for a 1/2 hour to see if something would reset.  No luck.  Then I went and disabled the auto lock feature at 15mph via programming. No luck.  Then I unplugged the RKE module up in the top of the dash. No luck.  I then tried unplugging the driver side and passenger side lock push-button switches.  No help.  I flexed the wires that are in a harness that go from the doors to the front frame of the van.  No luck.  The timing of the locking signal is not random. It seems to be always 30-35 seconds.  and it will do it with the driver side door open or closed.  So as to not drain this battery I unplugged the relay (in the junction block)that controls the locking of the doors.  My daughter has been driving the van for two weeks and says it starts okay now.  I also noticed that like when it is working properly, If I hold open one of the rear sliding doors, the fronts will lock at the timed interval, and as soon as I close the sliding door it will activate that lock on the sliding door.  Do you have any ideas for me?????
Thanks

Answer
Hi John,
The door lock system is mediated by the body control module which gets inputs from five different switches located in all doors and lift gate, as well as the RKE module and fob.
Because of this complexity the most efficient way to diagnose the system is with a diagnostic readout box at a dealer (DRB III). If you can get a readout of the body computer memory for fault codes related to the door lock and RKE system, specifically the wording of any specific fault codes, for a reasonable price then I do have the '98 body control manual and I can share the pages about that fault code with you by xerox copy and postal mail. There are about a dozen different codes so getting one specific code will narrow the search. So that is how I would suggest this be approached if you find that it will not be too costly to get a readout. I suspect that the typical commercial fault code reader will not access or report such codes and that the DRB III will be necessary. If you get a readout with a door lock code and want the pages about that code then send me a follow-up question where you tell me your postal mailing address. Also I assume that you have a vehicle theft security system, correct?
About the only simple trick would be to disconnect the battery clamps and then touch them together for a minute which resets some of the computers. Then reconnect the clamps, reset the clock and the radio presets, and see if that has improved the situation. Always disconnect forst and reconnect last the - clamp in the process so as to avoid a short circuit when handling the + clamp.
You can always choose to not use the power door lock system by simply securing the vehicle by means of the mechanical push-buttons and not using the RKE, the power door lock switches or the key (except the key to unlock the vehicle).
Roland