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LJS · 08-19-2019, 11:37 AM

I have an 07 Monaco Camelot with a Cummins 400hp engine. On a recent road trip I received an ALT/CHARGE alarm on the dash. Continued driving until I was able to find a place to pull off the road to check the problem. Found no obvious indications of possible causes. Started the engine and received the alarm again, both audible and visual. The charging voltage read approximately 13.6 volts.

After several minutes of driving the audible alarm stopped but the visual alarm remained lit. Continued driving while monitoring the voltage readout. Eventually the voltage dropped to approximately 12.1-12.2 volts, which indicated to me the alternator was failing.

Stopped at a Diesel/RV repair shop and they checked the alternator and said it was bad. Ordered a replacement and installed it the next day. After the replacement the voltages all checked good (alternator output, batteries, etc.), however the alarm failed to clear. The shop techs continued to troubleshoot but were puzzled as to the reason the alarm would not clear.

I contacted a shop that had done work for me previously and who were former Monaco employees and they said that Monaco used a proprietary alternator that was different than the standard alternators. They said one possible solution would be to have my original rebuilt.

I informed the shop foreman of this and he said the alternator was the exact same as the one that was removed. He said I could have my original alternator sent out to be rebuilt, which would take about a week, or I could keep the replacement installed and take the original with me and have it rebuilt later. I decided to leave the replacement installed, take the original and continue my trip. During the remainder of the trip the voltage remained at approximately 13.6 volts with alarm indicator illuminated (audible cleared after several minutes).

Before and at arrival home I noticed that with the generator running and the A/C on, periodically the power indication on the monitor display panel would go dark and the A/C would shutdown. The generator continued to run but with no load. Eventually the monitor panel would indicate power and the A/C would start. This has happened several times since and seems to be very intermittent. Could there be any relationship to the alternator issue or is this a separate issue, possibly a transfer switch problem? Any help would be appreciated.

waco kid · 08-20-2019, 06:15 AM

I,m not sure if will help you track down your problem,but when I had my 07 Scepter, I would get that same warning light and beeping when I had my engine running while I was still plugged in to 50 amps.....Bruce

LJS · 08-20-2019, 09:21 PM

In the past I also had the same thing. Eventually it would clear though. This issue seems to be a different problem. May just have to learn to live with it though. Thanks for your response.

YC1 · 08-22-2019, 07:33 PM

The combination of the onboard charger running and the alternator running at the same time can cause issues.

On my RV for example, the device that combines the batteries for charging has a disable function that disables it if the alternator is running and you have the generator running. This causes the converter and alternator to compete in some way and confuses things.

IF someone has modified your RV in the past to "solve a battery charge issue" and the two systems are being combined you can get these weird symptoms.

Try plugging into shoreline and running the engine to see if you get similar symptoms.

I found as have others that turning on the headlights to get a load on it seems to resolve the issue.

My combining system was in need of repair and I had a part that combined the batteries but would not isolate them when under the conditions mentioned.

LJS · 08-22-2019, 09:58 PM

Thanks for your reply YC1. In an attempt to duplicate the problem the day after my return home, without the engine running I disconnected shore power, started the generator, turned on the A/C and after approximately 20-30 minutes received the same indications as before--power panel display is blank and the A/C units shut off. After several minutes, power panel display appeared normal again and the A/C units started. I was able to repeat this several times that day. However, the next day I was unable to duplicate the problem after running the generator for several hours with the A/C units both running. Still scratching my head.

YC1 · 08-23-2019, 09:56 AM

Ok. You are most likely losing 12 volts to the air conditioners. It doesn't take a lot of 12 volts power to make them function.

If you lose 12 volts you lose the control of the units.

The 110 volts from the generator is still there it seems so that is not an issue.

Intermittents can be buggers to find and you need to be very methodical to chase one down or sometimes just plain lucky. I would rather be lucky that good any day when it comes to intermittents.

You need to be able to measure the voltage of the batteries without tugging, pulling, or moving things about. Leaving a compartment open and the battery trays pulled out if you have them is a good start.

Plan your attack. You need to get about three voltage measurements quickly when it is failing.

Starting with the center posts of the batteries. Check both banks just for good measure. Be sure to have a note pad at the ready.

Now find other places 12 volts might be under normal circumstances. For example, if you have a switch near the entry that controls a lot of things find the solenoid or solenoids it controls. Get measurements on those.

Be sure to have determined good sources of grounds to take measurement. If you need just get a long wire and connect it somewhere solid and use that as you move around the rv.

If you have schematics see if you can find a common source of 12 volts for the AC units and the display panel.

If you can get help have someone watch the dead display closely as you take measurements. One tiny bump can cure the problem temporarily.

50 years of chasing intermittents and I still have all of my hair. But I can stack up against any sailor for a cussing contest.

LJS · 09-17-2019, 09:02 PM

I think I may have resolved the ALT/CHG alarm problem. With the use of a wiring diagram obtained by an rv repair tech, found there is a fuse holder just off the alternator that holds two 5 amp fuses. One is for the ALT/CHG circuit and the other is for the IGN circuit. Found the fuse for the ALT/CHG circuit was blown. Replaced it several times during troubleshooting. Apparently the ALT/CHG relay was allowing the battery voltage (14.1v) across the 6v ALT/CHG alarm circuit which blew the 5 amp fuse. Replaced the relay and problem seems to be resolved. As for the generator and A/C problem, I am told it may be an EMS problem. Will troubleshoot this when I get a chance.

stillthinkin · 09-20-2019, 10:34 AM

This is the fuse holder I think you are talking about. In 2016 I found mine laying on the exhaust manifold, burned about half way through.
With help from Bill Willard, and his access to a wiring diagram, I learned it was a fuse holder for the alternator. I never would have guessed that.
I have yet to find a replacement cap, still working on it.