Onan QG 2500 not cranking, no control fuse found

[GT1]

The Onan RV QG 2500 LP generator stopped cranking on my Airstream Interstate, I believe it is related to winter driving, I drove about 10,000 miles this winter, and in one of these days the generator stopped working (can’t crank to start)

The manuals are clear, change the 5-amp control fuse, so I went under the RV and opened the cover and there is no control fuse :(

There is a circuit breaker, the start and stop button and the light, none of them are also working, but no control fuse to be found, like there is no place for a control fuse?

If anyone experienced the same issue, please let me know, there is most likely a control fuse for that specific model somewhere, but not as in the manual

[gjames50]

If you have the control fuse 5a (slow blow) you can see where it should be by going to this site. One of the pictures shows the fuse location.

Reset Onan Circuit Breaker

If you have an electronic governor the fuse should be a 10a fuse instead.

Maybe the holder fell into the compartment?

Good luck!

[GT1]

Thank you for the help, I saw that link earlier when searching

The Onan RV QG 2500 LP generator have an on and off button and a circuit breaker, but no place for a fuse that I can see, and that is very confusing

[gjames50]

Should be above your Circuit Breaker in your picture. Has it detached and fallen inside the housing/shroud?

I can't see an alternate location for that model. Maybe on the control board itself?

[GT1]

I am not sure if it detached, does not appear like anything detached, the manual is saying there should be a fuse, but the manual is also a copy and paste for many generators ☹

The irony is that no one has time to look at it for the next 3 months, and I spent days learning how to fix it, then found there is no fuse in the expected location 😊

It is also not easy to disconnect the entire thing, it is under the RV

[GT1]

Also, another thing that does not look right is the location of generator, under the motorhome! That is a very fragile location, it is exposed to water during driving, snow, and salt. It either has to be designed for that, or well protected

[whybother]

Some more photos around the genset's start/stop panel, breaker, etc., not cropped so the photos show more of the surrounding stuff for context, would be helpful.

Full model number (the super long thing including spec., etc., like: "2.5HGJBB-1121") would help as well.

Does it click when trying to start, or just nothing?

Going purely off appearance from your last photo, this may be the service manual for your genset:
https://rockymountaingeneratorsupply...e%20Manual.pdf
And parts manual:
https://rockymountaingeneratorsupply...s%20Manual.pdf

If yours is a HGJBB model, then I don't believe yours has a control fuse.

[GT1]

Update: I took it today to the mechanic, and they lifted the motorhome and disconnected a 9 pin cable that connects the generator to the RV, and none of the pins had any power in them.

No one was able to find any 5 amp fuse in the generator, so Onan QG 2500 LP has no 5 amp fuse I guess.

I have now to go through the Airstream Interstate schematics to find the next possible fail point.

[GT1]

It has been 5 months since this Onan Generator under the motorhome stopped working, and no one is able to fix it, lesson learned

1- Avoid the Onan QG 2500 LP (Loud Generators) at all cost!
2- Avoid in the future buying a motorhome with a generator under it, that is plain stupid

[gjames50]

Originally Posted by GT1

Update: I took it today to the mechanic, and they lifted the motorhome and disconnected a 9 pin cable that connects the generator to the RV, and none of the pins had any power in them.

No one was able to find any 5 amp fuse in the generator, so Onan QG 2500 LP has no 5 amp fuse I guess.

I have now to go through the Airstream Interstate schematics to find the next possible fail point.

No Power at all is strange. Have you checked the connections (main battery cables) that connect to the generator? On both the Gen and Battery ends. For many either a corroded connection or connector was the cause.

Some have said there might also be an Inline fuse/fuse link that could exist in one of the harnesses.

Your Onan Model Number and Serial Number might also help me. Can you post it?

Also the year and any more model details on your rig could also help.

I'll do some more digging and if I find anything I'll post again.

[gjames50]

The only thing of interest I could find is that I believe your 12VDC connection (main battery) to your Gen has no disconnect switch but should have Large Fuse(s) (possibly 125AMP).

Most everyone with a no-crank issue says it's probably battery cable related. Even the STUD on the Gen Set that passes through the Gen Housing can have a Snapped Connector to make sure power is going through those and inside to the gen itself.

[whybother]

I would start by checking for voltage at the positive and negative battery connection terminals on the genset, and make sure the connections are secure and free of corrosion:
https://www.norwall.com/product_pdfs...18.pdf#page=44

If you're getting ~12 volts there, then there's probably an issue with genset. If not, then follow those connections back, testing for voltage all the way, until you get to the RV's battery.

[96 Wideglide]

The fuse that protects the power cable to the gen starter should be much larger than 5A.

It 'should' be near the batteries.

[GT1]

Generator Info:

Onan QG 2500 LP
Model 2.5HGJBB-1121B Spec: B

I will be taking it to a new Generator maintenance place 200km from here this week, hopefully they can look at it.

The things that bugs me, I bought Airstream Interstate and paid the premium price for design and luxury, and still, these things are full with small issues.

And installing a generator under the RV and having it exposed to the weather, it is just not something that makes sense to me, we do drive this van in the summer and in the winter, on dry roads, wet roads, and snow roads.

Then the generator itself is full with electronics, these should not get wet!

Hopefully it gets fixed this week.

Thank you so much