No power when the generator is running

Bill, those two switches are your battery disconnects. One is for the main(chassis) and the other is for the aux(house). They are momentary switches. Press each and you should hear the relay click on or off as you press each way. They will isolate the batteries, but if you have ac power, the converter will supply dc. I suspect two situations. Your batteries are isolated and your generator breaker or breakers are tripped.

There are two switches just inside the door. These are next to the switch for the slide out , I'm not sure what they are for and couldn't find them in the manual.

There are two very common issues, one slightly common and some rare birds

Most common: On the generator there are usually 2 circuit breakers These are two position breakers, not the more comon (on/tripped/off) just on/off(tripped).

The ON/OFF markings are often a tad hard to see behind on the "Base" of the toggle.. (A flashlight may help shine the light on) and they may be in the OFF position.

Second: Has been covered above ("Generator outlet, manual transfer system, you plug into it)

Third (not so common: Faulty ATS.. (Automatic transfer system) Failed on mine, NOTE.. Many people will start the Generator while plugged in or, after a power fail, start the genny while plugged in and when power comes back shut it off.

Propercedure is to turn off big loads (Water heater, Space heaters, A/C, and the like, A/C's should be off for a minimum of 3 minutes, During that 3 minutes you change power sources.

Finally we have wireing errors, broken generators and other things.

ONAN generators (DO not know about other makes) are smarter than the average user,, If they are not making with the 120vac,, They think "Why waste fuel" and shut down.. So the fact it's running strongly
suggests the generator IS working.

Finally... Many RVers have a few screws loose... the kind that hold wires (loose nuts too, same kind).


Finally the Lights and water pump.. these are 12 volt devices.. Sounds like your house battery is not connected (STORE mode or AUX OFF mode).

Had a very similar problem last camping season. Searched and searched for loose connections, blown fuses, bad inverter/converter, bad transfer switch...... only to find that the, mostly hidden, circuit breakers on the side of the gen-set itself had tripped. Reset them and all was right with the world.....

I probably have a close setup to yours. Enblethen is correct about the 12v. Check your auxilliary and main battery switches next to the slide controls at the door. I would think that your power would auto switch(not a plug) like mine. If your microwave, tv or other ac items work on shore power but not the generator, I would suspect the auto switch or if your generator is not putting out at all, I would think that a breaker has tripped on the generator itself. There are two around to the side. Let us all know what you find. or if we can suggest something else to try.

There are probably two circuit breakers on the generator body. As mentioned above, someone may have hit the 12v isolation switch, often located by the entry door where it can be easily thrown in error. It is also possible (I learned from experience) that an error shorting out the battery while cleaning up could have blown the two 20 or 30amp fuses located on the inverter. In that MH the inverter was located under the kitchen cabinet way in back partially covered by the frig. Changing the fuses required laying down, squinting a bunch, and using a long needle-nose plier, but I got the job done.
Also, it is possible that your generator is plugged into the motorhome, not completely hard wired, in that case the plug may have come loose. Also in some motorhomes, rather than a transfer switch you must plug the generator into the motorhome, or plug shore power into the motorhome (haven't seen that for a while). Good Luck.

Hi,

Before automatic transfer switches there was an outlet (often in the shore power cord box) to plug the shore power cord into.

I still use that system. My RV is from 2004.

If genny has been working in the past maybe circuit breakers on genny need to be reset.

Lights should be operating off the 12 volt DC system
Failure of the lights could be the battery disconnect being off. Recycle that system.
Genset should be going through an automatic transfer switch. Normally located near the power center.
Have you checked the circuit breaker on the genset? Make and model of genset?