Onan 7500 33 code error
2003 Discovery with 7500 Non slide for generator
I have an onan 7500 worked fine had carpet guy there to clean carpets and generator stopped working. When I restarted the gen as soon as it takes a load it dies. Even when it switches over to charge the batteries thru the inverter it dies. I can turn the breaker off at the unit and it will run for hours no problem. Took to repair shop and error code reads 33. They said: 1 Governor actuator is binding 2 Readjust high idle speed 3Replace control assembly. They said we dont know what one is bad have to do all 3. Anyone else experience this. Thank you Joe SS/DA 69 Camaro |
Re: Onan 7500 33 code error
Joe, most likely your control module has failed ($$$). Adjusting the high-idle is all but a waste of time, but, just to be sure it wouldn't hurt to try it. Hate to be the bearer of bad news, but it is what it is, bud.
Just to be sure, are you thinking that cleaning the carpets had anything to do with your issue? |
Re: Onan 7500 33 code error
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Thanks for the reply, when I took it in for service, tech called the next day and said the block heater had short in it. I said where is that he said on the bed frame. So all i was thinking was the guy cleaning the carpets bumped it and caused the gen to quit. I said OK makes sense now. But that wasn't the case according to the tech he changed his mind after more investigation. Thanks again for the reply. Joe |
Re: Onan 7500 33 code error
I sent you a reply to your email
The generator needs to be load tested independent from the Coach. I use a 10kw resistive load bank to test all machines. I would disconnect the wires from your Coach to the Onan and connect my load bank and test the generator right up to its full rated output.... That's about 62 amps from memory.... This will verify if the issue is the generator or something in your coach and trust me it is possible your inverter or something else like an AC unit is the problem and not the generator... I have worked on and repaired many 7.5's and have not found the binding governor issue that Onan mentions in a service bulletin... The control is not a separate part. It is part of the generators inverter section and is only replaceable as a complete new unit. Very costly to replace......so the load test is a must BEFORE the unit is pulled out of the coach...... I've seen this problem before and it was NOT the generator..... The control unit section is all PC boards and the inverter section is the same....PC boards and high voltage components....all one sealed unit...... I've had 7.5's do some really unusual things......Start cranking the engine on its own with no switch signal to start. Had another one that would full field the generator end while trying to crank the engine. The starter would burn up trying to crank the engine. I just did one where the unit started cranking and smoked the starter.....Pulled it out and replaced the control/inverter section along with the starter and other parts....... Don't be confused when I say inverter. Your generator IS an inverter type machine and I'm not talking about the inverter in your coach.......2 totally separate things.... |
Re: Onan 7500 33 code error
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Thanks Rich We put a new inverter in this year, just so you know last one wouldn't power any outlets. I will try to find someone that can do what you suggested. Thanks again Joe |
Re: Onan 7500 33 code error
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When I turn the breaker off at the gen the gen will run for hours, when i flip the breaker on it waits about 15-20 seconds the raises idle and shuts off. I can almost hear the inverter click to start charging the batteries. Would that mean its on the coach side and not the gen. I asked a service tech he wasn't sure if he can isolate the gen from the coach. I need to find someone that can. Just wanted you to know about the breaker. I understand it doesn't have a load on it and thats what we need to check. Joe |
Re: Onan 7500 33 code error
It's very easy to Isolate the MH from the generator and test it with a resistive load bank.
The generator engine is speeding up because there is a load being sensed. We don't know if the shutdowns are being caused by the generator itself or the load being applied having some sort of short or feedback the generator senses as a short..... All your trying to do is eliminate the possibility of some issue in your wiring or inverter being the cause of the generator shutting down. Any proper Onan service tech or shop would know what I'm describing to do. Disconnect the output wires connected normally to the generator and substitute some other load.....and any decent generator shop has to have a load bank tester. Its nothing more than a big adjustable toaster......Resistors that turn electricity into heat... Your generator may just be shutting down because it is sensing something wrong down stream...….If it runs fine with the load bank connected it proves the problem is in your MH and the most likely issue is your inverter....Does not matter how old it is...... Does everything work ok when you plug in your shore power cord ? The generator may definitely have a problem but as I said you need to confirm it before doing all the work to remove it...... |
Re: Onan 7500 33 code error
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Yes everything works when plugged in. Last year with the bad inverter the gen would run until you plugged something in an outlet or turned on an A/C i tried each A/C individually, and both killed gen. Start gen without A/C it will run until you plug something then it dies. Reason we put new inverter in was nothing would run in coach unless we were plugged in, TV's, plugs no power to microwave nothing. Plug in everything would work. This year with the new inverter when it clicks over to charge batteries the gen dies. This year with the new inverter and gen is not running the inverter powers TV's, plugs, microwave, everything it should power without being plugged in or gen running. I will find an Onan service center. Thank you again for your help. MUCH APPRECIATED. Joe |
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