Safari battery isolator

[atomic98]

I have a 98 safari Serengeti that is giving me a problem..
At first it would not let 12 volt systems operate when plugged to shore power. Only after the rig is running, all works. Now the alternator is not charging. All batteries were teseted independently and are good. Is there a battery isolator back in the engine area, or am I fighting a ground or alternator problem?
Thanks
Greg

[GOLDWINGER2]

You should have the alternator tested. If it checks out OK move to the isolator and check for output at each terminal. If the isolator is good, start checking the wiring to each battery. Make sure all connections are clean and corrosion free.
J

[Robi.1014]

Something to consider: it appears that you have a "usage" problem and a "charging" problem.

Assuming your house batteries have a charge, then first troubleshoot why 12VDC systems (lighting, fans, etc.) are not working (as you indicated: these work "only after the rig is running").

Then, troubleshoot the charging path...and there are two of these: alternator and inverter/charger. Indeed: you may have a diode-based isolator that is failing or not correctly wired.