Classic Winnebagos & Vintage RVs

When I fired up the genny the other day I turned on the front AC unit and it ran. But I remembered that the last time I ran the units I had the rear AC on. So I checked the switch and the selector knob was on the rear meaning that the front should NOT be getting any power. So I tried various positions and both units will run no matter which position the switch is in. The good thing is, that when you turn the selector switch to off both units stay off. I have a 6.5 Onan that is in good shape but the plug is for a 30 amp service I believe. I can't remember if the selector works only when plugged up to shore power or I might have a bad switch. Any guesses?

Typical RV setup for Onan 6.5 with 2 AC's:
The 6.5 Onan has 2 separate outputs.  One is 30 amp, the other is 20 amp.
The 30 amp side is normally used to power the 30 amp shore power cable (let us say source 1).
The 20 amp side is normally wired directly to the rear AC (let us say source 2).

For those rigs with an AC selector switch, It was normally set up to select whether the shore power cable source (source 1) was supplied to the front or rear AC unit.  Sounds like, your switch swaps the sources back and forth when on generator power.  When front is selected, the shore power cable (source 1) runs the front AC and the genny (source 2) runs the rear AC.  When rear is selected, the shore power cable (source 1) runs the rear AC and the genny (source 2) runs the front AC.
On shore power only (from a campground post) and genny is OFF I suspect only the selected AC works.

I believe that's correct and I'm sure it is. I couldn't remember. I don't have a 30 amp shore power to try but maybe this weekend. Thanks Dave

My switch is set to rear an runs the front unit, I have no rear unit although it is wired for one. If I switch it to front then I have nothing. Somebody goofed.

Like Dave said.  Exactly how my '87 Winnebago is wired.


Rick  When mine is switched toward the rear the old label markings actually say front.  Go figure.

The selector switch worked when hooked to the 30 amp shore power.
This might be another topic but, when I didn't hook the shore line to the Genny outlet in the bumper ( manual transfer switch ). I could run 1 A/C unit and the fridge with the Genny running.

 :)ThmbUp good to know. Thanks Dave

Yep.  That's exactly how my switch works.  If its to the front and we are hooked up to shore power and no genny running, then it powers the front AC.  If its to the rear and we are hooked up on shore power and no genny running, it powers the rear AC.  If we are hooked up to shore power AND the genny is running, then the which ever position the switch is in, shore power is running that AC unit, and the genny is running the other.  If we are NOT connected to shore power, then if our switch is set to the front or rear, the genny will run both AC units.  Off is off for both AC units, either on shore power or genny power.

Kev

Anyone figured out how run both A/C off shore power?  I am thinking something like a power cord I could run to the 20amp plug on the power post to power one of the A/Cs while the 30amp connection does its normal thing.


It gets hot with one A/C.

There are several articles on here about doing just that, you need to do some wiring to makee it happen. You will have to do a search of the site for things like running both at once. I am terrible at search syntax.

I found it on a different site.  I used a Progressive Dynamics 30 amp automatic transfer switch off amazon.  Mounted it under the bed.  Wired in the separate circuit that feeds the rear AC from the generator to the "out" on the ATS.  Then wired the generator to the "generator" lead.  Wired in a 120V male plug in a waterproof connector (bought it at a marine supply store) out the back of the RV below the tail light.  Works great.  Now I can plug in my 30AMP main plug, and a separate 110v extension cord into the power pole at the campground and power both AC.