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Kiethco's avatar
Kiethco
Explorer
Jul 21, 2017

I've got a weird one

Last weekend in Lake Havasu, very hot and ran both ac full time while on shore power, 50 amp service. When we unplugged to come home I started the 7500 quiet diesel and only the rear a/c works on gennie power. The second I plug in, home or at a pole, they both blow cool. The front a/c does nothing while on gennie power. The rear ubit operates as normal.
I checked the breaker on the gennie, only saw one next to hour meter. I checked the inverter in the compartment and the panel next to the bed. All breakers engaged and not tripped.
I'm stumped.
__________________
Kieth and Ellen 1998 Holiday Rambler Endeavor 34 wds.
Usually towing our Manx dune buggy along
Enjoying sunny spots in So Cal and the Southwest.

10 Replies

  • Just got a call from Smith Powersports in Bellflower, CA. They're Onan gennie specialists and have some videos showing Onan service and maintenance.
    I took my coach there Wednesday and they gave me an update last night, said it was showing perfect on the meter and transfer switch. I told him I heard the transfer switch clicking after I smacked a few good one. It would switch after about 90 seconds and was buzzing which led to his diagnosis.
    So $500.00 and change and I'll be good to go with a new transfer switch.
    I also inquired about a remote generator start switch at my bedside. He said he can put as many remote start switches anywhere I wanted. I'm so pleased with these guys and I've been looking for someone close to Long Beach that does respectable, quality RV service.
  • My Cummins Onan RV QG 7000 generator has two 30A breakers on it - one for each leg. Original poster should check his again and turn both off, then back on before digging into the transfer switch possibilities.
  • Sometimes a breaker has to be flipped off and then back on to reset it. Been there and done that. Just looking it was hard to see the breaker had tripped with old eyes in a dimly lit BR
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Did you check the breakers on the generator? When that happens to me it has always been one of two things.

    When THE Motor Home was new... I had a problem with loose screws. I have a few friends who seem to think many RVers have a few screws loosese were the kind I tightened with a #2 Square Bit.. The wires in the power disribution center (Breaker Box) were loose. Sometime A/C worked, Sometimes the other, SSometimes both or neither.

    Since I tightened those screws (one took over 3 full turns) Every time that has happened... EVERY TIME.. It has been a breaker tripped on ye old Genny.. There should be two of them, likely 30 amp.. heat and vibratrion will turn them OFF.

    NOTE on mine the breakers only have ON and OFF positions, "Tripped" is off.
  • ONE Handle , its most likely a double pole 50amp breaker like in the main for breaker panel

    the quick check is to see what else does not work
    if one leg of the TS or genny is out
    only half the RV will have power, turn OFF the inverter/charger
    while doing this test
    you want only pass thru power from the genny
    check everything, wh, outlets, MW
    you have (3) possibilitys, genny, TS, Energy Management system
  • I agree with others that you may have a bad contact on the transfer switch, but it bothers me that you only see one breaker on a supposed 50A generator???
  • You might check your transfer switch. I believe there are 2 relays, one for each of the two lines on a 50 amp service. One may have a bad contact.
  • Simple. 50A has 2 "legs" (120V circuits). The A/C are on different circuits. Your generator either doesn't, or is not wired to, support both circuits.
  • Is there a transfer switch?

    If so one of the two legs may have burned contacts.

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