If your Onan is running but you are not getting any 120 volt AC power (e.g. the microwave oven or the air conditioner) inside your Roadtrek the most common cause is that the circuit breaker on the Onan has been tripped. Remember there is a couple of minute delay between the starting of the generator and the transfer of power into the Roadtrek. But if several minutes pass and you still have no power, it is likely that the Onan circuit breaker has tripped.
This is how you reset the Onan circuit breaker:
Step 1 : Locate your Onan. It is a green box with a black access panel. If you don’t know where it is located read this. It will either be behind an access door on your Roadtrek or hanging underneath in the rear center. If your Onan is underneath using some ramps made from 2x8 boards will provide a bit more working room.
Step 2: Remove the access cover. Put a finger in each of the latches and pull up and out to remove the access door.
Remember when you go to reinstall it that the latches are at the bottom of the door.
Step 3: Locate the Circuit Breaker. It may be difficult to see the little lever, but if you know were to feel for it, it is easy to find.
This is what you will see when you remove the access panel. The 25 amp AC circuit breaker is located on the side of the control panel below the 5 amp DC fuse and to the left of the fuel filter.
Step 4: Reset the Circuit Breaker. The off position is down and the up position is on. Don’t worry too much about the position, but reset by flicking it in the opposite direct and then back, but be sure to leave it in the up position.
You will probably never be able to see the view in the photo to the left. It was taken with the control panel removed from the Onan, but it clearly shows that the up position is labeled as On.
Step 5: Replace the Access Cover. Remember the latches are at the bottom. Make sure you get it on securely. They are expensive to replace, and must be installed to run the generator for more than a short test.
Step 6: You are done! Crawl out from under your Roadtrek or get off your bucket.