I have a 2007 Itasca sunova 35J house batteries charge when on shore power as well as when the generator runs, but not when driving. I've looked through the web and found that it's possibly the sol...
You can test the relay. Disconnect wires off one of the small posts, use an Ohm meter to check for continuity. Should be around 30 ohms. Have help operate the switch, and test for 12 volts DC on wire to small post. Other wire should have ground. This same relay should energize when the engine is running to charge coach battery(ies)