if you have 30amp service there is probably a switch to select front or rear air.

mikeyhsd@sport.rr.com

hello I just bought a 1994 Holiday Rambler  it has central air when I use
the Onan Marquis 7000 watt Generator they both work fine. when I turn off
the generator and plug unit into a only as a test to a 110v outlet the back
aircond does not start at fact it acts as if it has no power at all no
lights come on. could it be lack of power being plugged into a lower outlet
then is needed.

   thanks jack

We have the same thing on our coach, 98 Itasca, with a selector switch for
front or rear air, as we only have a 30 amp hookup. our rear air is wired
direct to the generator output. We plug the external power cable into the
generator out plug to get the front air and all of the ac equipment.

Leanne

That's the way they work. 30 amp service will not support both AC units,
running at the same time. Your generator puts 30 amps to the coach, and
front air, and 20 to the back ac

Somewhere you have a switch to select which ac you want to run.  You can run
both on a 7000 watt generator but not on 30 amp shore power.  The switch is
probably behind one of your overhead cabinet doors.

Don in Tracy, Calif.