Hey guys. All batteries are dead on our 2002 Fleetwood expedition.  Can we jump the Onan Generator at either one of these two points? TIA

Question on the Big Boy battery Isolator Relay;

On my 2002 Revolution I have a Big Boy isolator relay for the battery system.  Lately I have noticed that it has been making a very loud "thunk", like hitting your tires with a hammer. Sometimes its very loud other time its normal.

My first question is this relay repairable or serviceable?  Is it normal for it to be this loud?

Thanks

Larry