My blower Moyer runs with the key out a bell also starts chiming at random when the truck is sitting. Usually results in me needing a jump.

 

There have been problems with a junction box. Some of the problems were due to the windshield leaking and water getting into the Central Junction Box (CJB) under the dash.
All sorts of weird things would happen that were difficult and almost impossible to explain. Was the windshield in your vehicle ever replaced?