2017 Thor Palazzo charging house batteries underway

[unkel]

The House batteries on our RV do not charge while underway and the aux start button does not work. Has anyone else had these problems? do you have any fixes for them? Thank you.

[gjames50]

Originally Posted by unkel

The House batteries on our RV do not charge while underway and the aux start button does not work. Has anyone else had these problems? do you have any fixes for them? Thank you.

Probably the battery isolator relay (boost relay). You need to verify if it works or not. This relay connects your house batteries to the chassis batteries. There is usually a device that activates the relay to keep the house batteries charged from the chassis while driving.

Your Aux Start button manually activates this relay.

Good luck

[triplewide]

X 2 what gjames50 posted

[twinboat]

Get someone to press the boost start button on and off while you listen near the batteries. You should hear it clunking on and off.

If you do, that doesn't mean it's making a connection internally, they fail often.

[unkel]

It was the Aux start relay causing both problems. I replaced it and everything works as it should. Thank you all for your help!

[triplewide]

Thanks for posting your solution.

[WileyOne]

I've seen that problem before.

There is a cable that runs from the BIM (battery isolation module) to the house batteries. If somebody changed a house battery and neglected to connect that cable, the behavior would be exactly as you describe.