12v DC system failing sporadically
I have a 1997 Tioga Montara (Ford E350 V10 engine). Nice rig, works well. I disconnected from shore power 110v, and suddenly the 12v DC battery systems would not work. Lights, fan, water pump, etc...
Forum Discussion
This sounds like a loose connection to me, as well. I would start by verifying all the wires and connections at the batteries, the positive and grounds and battery interconnect wires. I have seen cases where battery cables corroded internally, within the insulation, to the point of being disconnected (or nearly so) while outwardly appearing sound at first glance.
Also check the ground connection at the frame from the battery ground cable and clean/tighten if needed. The fact that things work well when connected to AC power seems to indicate that the main 12V wiring is in good order and the problem lies somewhere along the wiring between the batteries and the rest of the system. It's not a guarantee that your problem is there, as electrical problems can be quite subtle, but it's a pretty good indication.
Also check the ground connection at the frame from the battery ground cable and clean/tighten if needed. The fact that things work well when connected to AC power seems to indicate that the main 12V wiring is in good order and the problem lies somewhere along the wiring between the batteries and the rest of the system. It's not a guarantee that your problem is there, as electrical problems can be quite subtle, but it's a pretty good indication.
