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cokerstrom · 06-25-2022, 09:36 AM

Many thanks to Engine Generator Specialist in Madison, WI for solving our problem and getting us back on the road during a very hot summer. I highly suggest contacting them if you're in need and in the area.

Since I didn't find a recent post with the symptoms we saw, I wanted to put it in a post to document this if someone else hits this issue.

Halfway through a 3 week road trip our Onan QD 10K just suddenly doesn't crank. I can hear the tick-tick of the fuel pump primer, but no cranking and an error code 32 (slow cranking). Battery power to the unit is good. Seems like a solenoid problem.

It's hot as hell and our dash A/C is not cutting it, so I contacted Engine Gen Specialist and they got me in in two days. And better yet, they found that the problem was a $12 relay on the circuit board. This relay is used to fire the solenoid. According to Stewart (the tech) there are 3 of these identical relays used on the circuit board, each controlling several items like fuel pump, solenoid and I forgot what else. So I purchased a 2nd as a spare!

So a happy ending and a low cost fix -- woo hoo!

Hope this helps someone else.

Chuck

Tim Fox · 06-25-2022, 09:43 AM

Best kind of post! You had a problem, identified the solution and got away relatively unscathed. Thanks for posting.

LWBAZ · 06-25-2022, 08:18 PM

Quote:

Originally Posted by cokerstrom

It's hot as hell and our dash A/C is not cutting it, so I contacted Engine Gen Specialist and they got me in in two days. And better yet, they found that the problem was a $12 relay on the circuit board. This relay is used to fire the solenoid. According to Stewart (the tech) there are 3 of these identical relays used on the circuit board, each controlling several items like fuel pump, solenoid and I forgot what else. So I purchased a 2nd as a spare!

On the Onan 10000 & 12500 generators, the circuit board (also known as the control board) is a sealed part - see attached photos. There are three relays located close by, but they're not part of the control board.

The good news is that, as you found, the relays are not expensive. The control board, well, that's a different story.

426smartin · 06-25-2022, 08:51 PM

Got a part # for the relay?

LWBAZ · 06-25-2022, 09:30 PM

Quote:

Originally Posted by 426smartin

Got a part # for the relay?

Might not be the same relays on all Onan diesel generators, but the attached page from an Onan parts manual shows the three relays and a part number for them - see yellow highlights on the page.

LWBAZ · 06-25-2022, 09:36 PM

Below are a couple of photos showing what I’m reasonably sure are the relays Onan uses. Hopefully, Chuck (“cokerstrom”) will let us know if the spare relay he purchased looks similar if not identical to these photos.

Mwoodofd · 06-26-2022, 04:05 AM

Thanks for the post Chuck and the detail and parts Larry - going to get a few to have in the fuse and relay parts kit.

426smartin · 06-26-2022, 07:12 PM

Thanks!!

cokerstrom · 06-27-2022, 07:48 AM

The part number shown on the package for that relay is A040G405.

Regards,

Chuck

LWBAZ · 06-27-2022, 07:11 PM

Quote:

Originally Posted by cokerstrom

The part number shown on the package for that relay is A040G405.

Regards,

Chuck

Thanks for that info, Chuck. Fortunately, that's the same part number that's highlighted on the page from the Onan parts manual I posted above. I'll include that page again with this post.