Originally Posted by pokeybait1
my new, used, 34j keeps running the cab battery down as the household batteries drain. I had to put a knife switch on the negative side of the cab battery to keep it charged when shore power or generator is off. I thought an isolator would trip if this happened to separate the circuits.
Do should have a switch that allows you to start the truck using the house batteries in case the cab batteries go bad. If so, check, make sure it is off or not stuck in the on position.