On my “new” 1989 Dodge B250 camper van, the existing battery died once or twice just after I bought the van, so I just thought it was old, and I got a new battery. New battery worked great…then I parked the van for a week, came back, tried to start it…battery totally dead.
So there’s definitely a phantom load somewhere. Now, I did suspect a phantom load when the old battery died. The van’s wiring has been modified by previous owners to allow the engine battery/alternator to charge two 12V auxiliary batteries in the back of the van. But there’s a manual toggle switch that disables the charging circuit, and i left that switch ij the off position. Furthermore, the charging circuit is disabled with the ignition switch in the off position. I verified this with the old battery before replacing it.
So I convinced myself that the charging circuit was not the source of the drain, and that the existing battery must have just been old.
But, now with the new battery totally dead, obviously there is still a phantom load.
Question is: what are the possible sources of the drain, and how do I go about tracking it down?