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
The DC works when your plugged in which would seem to indicate that your converter is working - you can double check that by using a multi meter and taking a reading (preferably at the converter).
Your rig has a battery cutoff switch - often a momentary toggle switch maybe located near the door of perhaps near the drivers left knee in the cab - make sure that's working properly and not stuck in the off position.
Another possibility is defective auto reset circuit breaker often located near your coach battery. Here's a link to what it might look like https://www.amazon.com/MonkeyJack-Reset-Circuit-Breaker-Automatic/dp/B075GRYFTL/ref=sr_1_10?s=automotive&ie=UTF8&qid=1505816112&sr=1-10&keywords=auto+reset+circuit+breaker+12v
You should also have your batteries tested - any tire or auto shop will perform for free. If you have lousy batteries then they will only hold a charge for a short period of time which would explain why you lose power when you disconnect from shore power. The battery status indicators on RV's are worthless so don't rely on them.
When I had phantom 12 volt issue I finally tracked it down to a loose battery wire - apparently the connection between the wire and terminal ring (hidden under shrink wrap)came loose. That was a nightmare to track down.
Your rig has a battery cutoff switch - often a momentary toggle switch maybe located near the door of perhaps near the drivers left knee in the cab - make sure that's working properly and not stuck in the off position.
Another possibility is defective auto reset circuit breaker often located near your coach battery. Here's a link to what it might look like https://www.amazon.com/MonkeyJack-Reset-Circuit-Breaker-Automatic/dp/B075GRYFTL/ref=sr_1_10?s=automotive&ie=UTF8&qid=1505816112&sr=1-10&keywords=auto+reset+circuit+breaker+12v
You should also have your batteries tested - any tire or auto shop will perform for free. If you have lousy batteries then they will only hold a charge for a short period of time which would explain why you lose power when you disconnect from shore power. The battery status indicators on RV's are worthless so don't rely on them.
When I had phantom 12 volt issue I finally tracked it down to a loose battery wire - apparently the connection between the wire and terminal ring (hidden under shrink wrap)came loose. That was a nightmare to track down.
