Next issue with 'this old van'...the two buttons on the front doors will lock the van, but not unlock it. Turning the car on locks the doors, putting it in park does not unlock the doors, but turning it off does. The key fob lock and unlock functions work correctly as always. Could this be the switch in one of the doors gone bad? I have tried to trace the schematics but cannot seem to find anything that makes sense to me. Any input would be appreciated.