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Power Lost With Genset Running

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2003 Onan Quiet 7500 has been running like a top for the three months we have owned the coach, but yesterday it started fine but no power to the coach. I checked the main/ ok but I reset it anyway. Heart inverter has two breakers/ I reset them. The 35 amp on the generator was not tripped, but I reset it also. That one has a light throw. Maybe runs a relay?

I am thinking ATS, because everything was fine the day before. I had the cover off recently to check for loose connections or apparent heat related discoloration. Everything looked good, but it is over 11 years old. It was raining yesterday so I did not want to get the multimeter out with a running genset. Headed back over today for some analysis. Suggestions will be appreciated!!! 40ft 2003 Phaeton Lyght 50 ATS.

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The neutral wire of the wiring harness on ours came loose several years ago. We had to have the entire harness on the generator replaced because of arcing that had been happening. That caused a condition like you describe. There is a connection box with a small removable cover on one corner of the enclosure. That is where the generator output is routed to connect with the conduit to the coach. If you have checked connections, check again just to be sure that all contacts are clean and secure.

The other possibility is the transfer switch which transfers power from the shore power source to the generator power source. I've also replaced one of those on our first coach. That is an automatic switch on most coaches so there isn't any control you can look for to replace. The control sensor is built into the unit.

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Will look for that tomorrow. Cover comes off of the ATS now that the rain has quit. Will check for 120 in from genset. Nothing there will tell me to work upstream to the junction box you mentioned. If that is not the problem I will have to trouble shoot the genset breaker. If that is good, I am in trouble. I really hope that it is either the transfer switch or the coach's main breaker. I ordered a new transfer switch today to have as a backup on our trip or to install if the current one is bad.

What year was your generator? Thanks!!

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Ours is a 2004 coach which we bought in November of 2003 so I suspect the generator is a 2003. It is a 7.5 KW.

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It was the automatic transfer switch. I would not have known to suspect it without the info available on this website. Didn't have them in 1988. Our gasser was setup for 50 amp service but you only had 2 choices/ shore power or generator. There were no inverter chargers that I remember reading about. When you unplugged from park power you plugged in to an overhead 4 prong plug that was the output of the 6000 watt genset. That way you could run a rooftop ac or a microwave for snacks.

Anyway/ thanks FMCA forum for the knowledge and the replacement arrived a day early. I know where I will be tomorrow.

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I had 1/2 of my transfer switch go out. Usually, this is a non maintenance item. Upon inspection, I found corrosion all over it as the coach sat idle in Fla for a couple years. No humidity in Fla to cause corrosion :)

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You know you are right! No humidity in FL is why there is so much Spanish Moss hanging from the trees. That stuff likes a desert environment!!!

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Don't know where it was, but the salt air mixed with the "no humidity", will corrode a glass window. LOL

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