Thursday, February 2, 2023


Why did RV’s lights and fridge stop operating on generator?

Dear Dave,
Recently I turned the generator on and, like always, it came on, but my inside lights, fridge and all did not come on. I plugged in my shore plug, and all came on. What could be the issue? Any troubleshooting I can do? This has never happened in my years of owning it. Doesn’t appear to be blown breakers or fuses on hallway floor panel. Help. —Janis, 1995 Rexhall Aerbus

Dear Janis,
Let’s first take a look at the components you have listed and what power they run on. The interior lights run off the 12-volt deep cycle house batteries and the refrigerator is either 120-volt power or LP. I’m not sure what other appliances you are referring to.

Now, let’s look at the shoreline cord versus the generator, both of which will supply 120-volt power to the distribution center. What could be an issue here is how the power comes to the coach: You either have an automatic transfer switch (ATS) or a “J” box.

How the ATS works

The ATS has the shoreline cord wired to it as well as the line coming from the generator. When the generator is running and supplying power, it senses that and automatically switches inside the box to allow power to flow from the generator to the distribution center. When you plug the shoreline cord into a campground source and the generator is off, the ATS switches to the shoreline cord.

If you do not have an ATS, then your rig has a “J” box with the line from the generator wired to it. You need to physically plug the shoreline cord into it to get 120-volt power from the generator.

If the lights do not work when the unit is not plugged into a campground source, my first step would be to test the house batteries. They should power them and are most likely sulfated and actually dead. When you plug into the shoreline, the converter kicks in and provides 13.6 volts until the batteries are charged, then drops to a float charge of 13.2 volts. So, you need to use a multimeter and check the batteries with no power coming in, then plugged into shoreline power, which I believe you will see 13.6 volts, and then unplugged with the generator running.

If you are not getting 120-volt power with the generator running, I would first check the shoreline cord and see if it needs to be plugged into the “J” box. In either case, if you are not getting 120-volt power from the generator, check the circuit breakers on the generator. You should have a 30- and 20-amp breaker directly on the generator.

Otherwise, there is an issue with the ATS not switching or the “J” box with an open connection.

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I replaced the fuel line, now the generator won’t start

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I have an Onan genset in our 94′ Winnebago Class A Vectra. I am unable to start it! It worked perfectly prior to my changing the rubber fuel line link, due to age cracking, between the metal vehicle line and the input side of the fuel pump. I have checked and rechecked all fuses, wiring, etc. I even tried blowing in the rubber input line! Putting fuel in a can and disconnecting the fuel line at the carburetor reveals no fuel intake by the pump. I tried filling the rubber line to the pump and from the carburetor to no avail. Is there some sort of airlock or priming method I need to do to reactivate the pump? I am stumped! Thank you. —Doug W.

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Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

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28 days ago

About 20 years ago my Onan gas generator had an internal part go bad such that even though the generator would start and run fine, no power would come out of it. It’s been too long for me to remember the fix that was done, but it was in the Nashville Onan facility about an hour for diagnosis and part replacement and the bill was something under $100 back then.

So while the items Dave mentions are a first good check, there might be an internal component in the generator not allowing power to be produced.

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