Help with an 87 El Dorado motor home

[Mike J]

I recently purchased an old El Dorado motor home primarily to use as a mobile hunting shack.

i have some basic questions about how some things work, or are supposed to work.  The guy I bought it from inherited it, and never used it, knows nothing about it.

To start...

Isn't there a battery for the house lights?  So, they work even if not hooked into power?

There's a second battery in the engine compartment, on the drivers side.  What is it's function?

If someone is familiar with this motor home, I sure would appreciate picking your brain a bit.

[Lakota Wolf]

with 2 batteries under the hood,, 1 is for the engine and the 12nd is your cabin battery for interior lights, heater blower motor,electric water pump and stove vent fan.

[Mike J]

Well, thanks, that is what i thought, but, it must be so dead it doesn't take a charge.

1 more question if I could bother you....there is a switch on the drivers seat, on the left side.  It says battery on it, and just on and off.  What is that for?

[Mike J]

Back to the second battery.  Does the position of the ignition key matter?  I get no house lights even with a charger on the battery.  If i turn the ignition key to AUX, I get house lights.  When I put the key back to the lock position, the lights stay on

[Rich Thomas]

The way mine works is through a relay. the relay picks up when the key is in the start or run position and allows the alternator to charge the coach battery while the engine is running. Conversely it drops out when the ignition is off. This keeps the coach functions from draining the chassis battery. The switch you have may be a manual way of doing this same function. It is hard to say by not actually seeing your rig. A good meter and a second set of eyes would help you to chase out the circuit but this should at least give you a direction to head in. Good luck with your project.