Chances are that the relay that charges the coach battery is bad on your RV. Mine went bad with about 4 years old or 15,000 miles on my 97 Bounder. I installed a 100 amp rated forklift relay, that has a 12 volt coil, silver allow contacts rated to open and close 100,000 times.
Grainger part number 6C017
I ran a new #4 wire from my alternator to the relay, then a 100 amp fuse, and to the golf cart battery.
I have a three way switch, with on-off-on and +12 from my radio to one side, +12 volts from the engine battery to the other side (so I can turn it on to charge the engine battery while parked or to boost the engine battery while starting it with the coach battery). This will turn on the relay automatically with the engine when in the radio on position.
I have 5 amp fuses on the low amp wires going to power the relay.
I never did find the factory relay, and will not look for it.
Good luck,
Fred.
Money can't buy happiness but somehow it's more comfortable to cry in a
Porsche or Country Coach!
If there's a WILL, I want to be in it!
I havn't been everywhere, but it's on my list.
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