Home » Public Forums » GMCnet » Onan / Electrical problem
| Onan / Electrical problem [message #115586] |
Fri, 18 February 2011 19:26  |
thorndike
Messages: 406
Registered: January 2011
Location: Conifer, Colorado
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As I was working on my GMC today, I attempted to start the generator as I had never heard it run from outside, I have always been inside the coach when it was running. It gave me trouble free operation during my jaunt from New Mexico to DC, and I had no problems whatsoever. The Onan fired up readily each time.
I looked into the generator compartment and noticed that the negative cable was loose on the battery. So I tightened it up thinking that was the problem. No dice.
I checked the breaker on the top of the Onan, it did not need to be reset. I then checked the breaker at the panel and recycled it to be sure, but no dice.
The generator makes no effort to start, so I am fairly sure it is an electrical problem. Are there any other breakers or fuses I should be aware of? Any thoughts on where to look first before I start tracing the cabling back looking for bad connections?
Bob
Robert Peesel
1976 Royale 26'
Side Dry Bath
Conifer, Colorado
[Updated on: Fri, 18 February 2011 19:27] Report message to a moderator |
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| Re: Onan / Electrical problem [message #115613 is a reply to message #115586] |
Fri, 18 February 2011 21:07  |
Craig Lechowicz
Messages: 541
Registered: October 2006
Location: Waterford, MI
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Bob,
All the breakers you checked are on the 110 volt AC side of the generator, and would affect whether the generator fed the coach power when it was running. Your problem is on the 12 v. side of the system. I don't remember what kind of coach you have, but newer ones like mine ('77 but started before then) have a "house" 12 volt battery that powers things like interior lights, vent fans and such in the coach, and also supplies the cranking power to the generator. So, simplest and most likely case is that battery is dead. The coach would still start the propulsion motor off the front battery. The house battery is charged when plugged in by the converter. The batteries are also connected for charging when the 455 is running by the isolator on the passenger side firewall. They can also be connected through a heavy #1 guage or so cable through the battery boost switch on the dash. More on that later if the rear battery continues to not stay charged. But, to 1st get the generator started. Verify the house battery is charged. Are you using the start switch on the Onan, or the remote switch in the coach? The remote switch has a connector inboard of the generator compartment underneath the coach that often fails. The starting circuit itself is battery ground cable to frame. Frame to onan. On the positive side, battery to a relay that controls the boost function but doesn't otherwise affect the generator by the battery. From there to the starter solenoid on the Onan. There's a whole further diagnosis for whether the Onan switch operates starter relay, but my guess is that it's either a low battery, or a loose battery cable. If that doesn't solve the problem, you'll get more and longer notes.
Craig Lechowicz
'77 Kingsley, Waterford, MI
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| Re: Onan / Electrical problem [message #115647 is a reply to message #115586] |
Sat, 19 February 2011 00:48 |
Luvn737s
Messages: 1106
Registered: June 2007
Karma: 2
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Are you saying you tried to start it from the genset itself or the remote switch inside the coach? Did you try jump-starting it off another battery?
Randy
1973 26' Painted Desert
Ahwatukee (Phoenix) AZ
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| Re: Onan / Electrical problem [message #115653 is a reply to message #115613] |
Sat, 19 February 2011 02:47 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
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From the bottom of the first post: "1976 Royale 26' Side Dry Bath".
Royales, especially the earlier ones, have an odd ball set-up for batteries. (At least from the factory.) They had one 12 volt battery back by the gen set wired to start the generator. They had two 12 volt batteries up front... A chassis and a house battery. (This much sounds like a '73/74 GMC upfitted coach.) BUT unlike the early GMC coaches, someone at Coachman thought it would be a good idea to wire both the front "house" battery and the rear battery together as a single house bank. While paralleling batteries "works" it doesn't help with battery life. Paralleling with a long cable between them makes it even worse.
Basically... I think you have bad or dead battery(s).
Start the coach motor and turn on the boost switch and then try and start the gen set. (Effectively jumping the generator.)
IF I owned a Royale, I would convert it two a later model "GMC like" system but use two 6 volt golf cart batteries for a house bank. My Birches (23 foot, by Coachman) do not have space for a rear battery.
| Craig Lechowicz wrote on Fri, 18 February 2011 19:07 |
Bob,
All the breakers you checked are on the 110 volt AC side of the generator, and would affect whether the generator fed the coach power when it was running. Your problem is on the 12 v. side of the system. I don't remember what kind of coach you have, but newer ones like mine ('77 but started before then) have a "house" 12 volt battery that powers things like interior lights, vent fans and such in the coach, and also supplies the cranking power to the generator. So, simplest and most likely case is that battery is dead. The coach would still start the propulsion motor off the front battery. The house battery is charged when plugged in by the converter. The batteries are also connected for charging when the 455 is running by the isolator on the passenger side firewall. They can also be connected through a heavy #1 guage or so cable through the battery boost switch on the dash. More on that later if the rear battery continues to not stay charged. But, to 1st get the generator started. Verify the house battery is charged. Are you using the start switch on the Onan, or the remote switch in the coach? The remote switch has a connector inboard of the generator compartment underneath the coach that often fails. The starting circuit itself is battery ground cable to frame. Frame to onan. On the positive side, battery to a relay that controls the boost function but doesn't otherwise affect the generator by the battery. From there to the starter solenoid on the Onan. There's a whole further diagnosis for whether the Onan switch operates starter relay, but my guess is that it's either a low battery, or a loose battery cable. If that doesn't solve the problem, you'll get more and longer notes.
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Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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| Re: Onan / Electrical problem [message #115671 is a reply to message #115647] |
Sat, 19 February 2011 09:40 |
Larry C
Messages: 1168
Registered: July 2004
Location: NE Illinois by the Illino...
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Did you try to start from the inside only? Did you try to start at the GEN SET panel on the gen?
The cable on my 74 has a connector at the rear of the gen set cabinet. You can only reach it by taking the heavy genset OUT OF THE CABINET. those connector contacts are known to corrode then the inside starter switch will not start the genny.
Mine does not work from inside and I am fairly sure it is because of this connector but I don't have resources to take the genny out so I start it at the genny.
One other thought, when I originally brought my coach home, the gen set did not work. The PO ran a wire from the door ( remote start panel ) over the floor to the gen battery. He said it would not start without it but he did not know why.
My vehicle battery kept losing charge and it turned out to be the battery at the gen compartment. The wire he installed tied the system to the vehicle battery. The Gen batt was shorted inside and drained all the power out. The gen was starting because it was getting Vechicle power via the wire the PO ran over the floor.
Check the condition of your battery.
my thoughts
Gatsbys' CRUISER  08-18-04
74 GLACIER X, 260/455-APC-4 Bagg'r
Remflex Manifold gaskets
CampGrounds needed, Add yours to "PLACES" />
http://www.gmceast.com/travel
_
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| Re: Onan / Electrical problem [message #115709 is a reply to message #115653] |
Sat, 19 February 2011 14:40 |
thorndike
Messages: 406
Registered: January 2011
Location: Conifer, Colorado
Karma: 0
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Well, we just tried to 'jump' the generator by attempting to start it from the panel while holding the boost button in on the dash. Nothing happened. While it is possible both batteries are dead, I would doubt it.
Looks like it is time to check the other connections and switches.
Bob
Robert Peesel
1976 Royale 26'
Side Dry Bath
Conifer, Colorado
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| Re: Onan / Electrical problem [message #115712 is a reply to message #115653] |
Sat, 19 February 2011 14:46 |
thorndike
Messages: 406
Registered: January 2011
Location: Conifer, Colorado
Karma: 0
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Mike, thanks for the information. It looks like I have the standard Royale battery configuration. I have one in back with the Gen. and two up front.
If the batteries are good and the problem is a bad connection somewhere, I will fix the bad connection and keep things as they are at the moment. Once I have a dead battery though, I will look at reorganizing and getting the two 6v batteries installed.
Everyday I learn more and more about what I don't know!
Robert Peesel
1976 Royale 26'
Side Dry Bath
Conifer, Colorado
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| Re: Onan / Electrical problem [message #115729 is a reply to message #115586] |
Sat, 19 February 2011 16:10 |
thorndike
Messages: 406
Registered: January 2011
Location: Conifer, Colorado
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Well, I pulled the gen out and located the panel on the side. I was a bit surprised to see that there were no buttons, just holes in the cover plate where buttons belonged! Where the start button WAS located, there was still a little push-button switch that was obviously triggered by a larger button at one point.
I pressed the switch and nothing. So Unless the batteries are dead, it looks like a bad connection between the batteries and the gen.
I think I will wait for slightly warmer weather.
Bob
Robert Peesel
1976 Royale 26'
Side Dry Bath
Conifer, Colorado
[Updated on: Sat, 19 February 2011 16:11] Report message to a moderator |
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| Re: Onan / Electrical problem [message #115735 is a reply to message #115586] |
Sat, 19 February 2011 17:25 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Quick test.... are your 12V house lights working? If no the house batts are most likely dead/bad connections. If they are bright do they stay bright when you attempt to start the Onan? Then the Onan is not getting 12v or not getting a start connection from the panel. If house lights are dim or out you need to charge/test/replace house batteries/ clean connections. With the main engine running can you use the boost switch to try to start the Onan or to get house lights if they are out?
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Onan / Electrical problem [message #115881 is a reply to message #115735] |
Sun, 20 February 2011 17:24 |
thorndike
Messages: 406
Registered: January 2011
Location: Conifer, Colorado
Karma: 0
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Senior Member |
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Yep, it appears that all the internal 12v systems work. With the engine running the onan is still inoperable.
I returned the GMC to it's parking spot this weekend and have a big work project going on, so I won't be able to see if the lights dim when I try to start the gen.
I have plans to get back to it this coming weekend. It is just as well, work has ruined my three day weekend anyway.
Bob
| JohnL455 wrote on Sat, 19 February 2011 18:25 |
Quick test.... are your 12V house lights working? If no the house batts are most likely dead/bad connections. If they are bright do they stay bright when you attempt to start the Onan? Then the Onan is not getting 12v or not getting a start connection from the panel. If house lights are dim or out you need to charge/test/replace house batteries/ clean connections. With the main engine running can you use the boost switch to try to start the Onan or to get house lights if they are out?
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Robert Peesel
1976 Royale 26'
Side Dry Bath
Conifer, Colorado
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| Re: Onan / Electrical problem [message #115925 is a reply to message #115882] |
Sun, 20 February 2011 20:39 |
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mike miller
Messages: 3576
Registered: February 2004
Location: Hillsboro, Oregon
Karma: 0
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Your generator start/stop switches.
From your statement from your first post*, I assumed you had started the Onan from inside the coach.
*The statement: "As I was working on my GMC today, I attempted to start the generator as I had never heard it run from outside, I have always been inside the coach when it was running."
| thorndike wrote on Sun, 20 February 2011 15:25 |
Mike, which 'inside' switches are you referring to?
| mike miller wrote on Sun, 20 February 2011 04:34 |
| thorndike wrote on Sat, 19 February 2011 14:10 |
Well, I pulled the gen out and located the panel on the side. I was a bit surprised to see that there were no buttons, just holes in the cover plate where buttons belonged! Where the start button WAS located, there was still a little push-button switch that was obviously triggered by a larger button at one point. ...
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Sounds like you have been "PO'ed" !!! 
(One of your "Previous Owners" (PO) has made changes to your coach. While I should have thought and asked... )
Some PO modifications are good... many are not.
I suspect the board had a problem (it IS old technology) and wired the inside switches as the only way to start it. The board on the original Onan control board has a rocker switch for starting and stopping. It also has a couple of relays sticking through the cover. Some have added a prime button that might be located near there.
You didn't say but do the inside switches still work?
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Mike Miller -- Hillsboro, OR -- on the Black list
(#2)`78 23' Birchaven Rear Bath -- (#3)`77 23' Birchaven Side Bath
More Sidekicks than GMC's and a late model Malibu called 'Boo'
http://m000035.blogspot.com
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