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Biggyniner's avatar
Biggyniner
Explorer
Jul 28, 2015

Auxillary Start/battery solenoid

Hi All..

I think I know the answer but I'm open to feedback/suggestions...

So I was doing some testing to my Minnie and come to find out the engine is not charging my house batteries. If I depress the AUX start button I hear an audible click, so I believe the relay works in that regard. I tested the house battery solenoid with the engine running and I do have ~14.5 volts on the chassis side of the solenoid and then just 12.8ish volts on the house side - the same amount that was there with the engine off. The generator/shore power will charge the house battery.

Before I swap the solenoid out is there anything else I should check? I hear there should/could be a fuse somewhere for this solenoid, would it be in the chassis fuse panel?

Thanks
Class C

19 Replies

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  • Crem's avatar
    Crem
    Explorer
    Jul 29, 2015
    About 5 years ago I had the same problem on my 2003 Itasca. I removed the solenoid and using my grinder I ground around the edge of the top cap on the solenoid so that I could remove the top. I was then able to clean up the inside contacts and tack weld the cap back on again.
  • tenbear's avatar
    tenbear
    Explorer
    Jul 28, 2015
    The solenoid in my rig is energized when the ignition is on. There is also a circuit breaker in series with the solenoid contacts. Since you are not getting the same voltage on both sides of the solenoid when it is energized, the solenoid is not making contact, the circuit breaker or fuse is not in the picture.
  • enblethen's avatar
    enblethen
    Nomad
    Jul 28, 2015
    On my rig, when the chassis reaches a set value, the charge relay energizes. The charge relay and the aux start is the same relay on my rig.
    It has a separate ignition relay that energizes to provide power to coach manufacturer installed items.
  • Beverley_Ken's avatar
    Beverley_Ken
    Explorer
    Jul 28, 2015
    I believe that there are 2 different relays/solenoids. One for the boost feature that connects the house batteries to the chassis battery and a second that allows the house batteries to be charged from the chassis

    ken
  • ron_dittmer's avatar
    ron_dittmer
    Explorer III
    Jul 28, 2015
    Biggyniner wrote:
    ron.dittmer wrote:
    I believe motor home battery charging is prioritized such that the chassis battery will get charged first, then switches over to the house batteries. If your chassis battery needs to be charged, then you will get the measurements you are seeing.
    I was curious about that.. My father had an isolator in his pickup for his truck camper that worked as you described... but I believe on my system it should pass the charge through to both batteries anytime the engine is running. I forgot where I heard/read this....
    I never heard of shared charging, but I am no expert on this subject matter.
  • Biggyniner's avatar
    Biggyniner
    Explorer
    Jul 28, 2015
    ron.dittmer wrote:
    I believe motor home battery charging is prioritized such that the chassis battery will get charged first, then switches over to the house batteries. If your chassis battery needs to be charged, then you will get the measurements you are seeing.


    I was curious about that.. My father had an isolator in his pickup for his truck camper that worked as you described... but I believe on my system it should pass the charge through to both batteries anytime the engine is running. I forgot where I heard/read this....
  • ron_dittmer's avatar
    ron_dittmer
    Explorer III
    Jul 28, 2015
    I believe motor home battery charging is prioritized such that the chassis battery will get charged first, then switches over to the house batteries. If your chassis battery needs to be charged, then you will get the measurements you are seeing.

    If you have a battery charger, I would charge the chassis battery that way to assure it is fully charged. Then start and idle the engine for a few minutes, then measure again. You are trying to get the electrical system to switch over to the house batteries. If you can't make it happen, then with the engine running, hook up your battery charger to the chassis battery and measure again.
  • enblethen's avatar
    enblethen
    Nomad
    Jul 28, 2015
    Just be cause it clicks doesn't mean it is making contact.
    Appears you need new relay. NAPA stocks them. Make sure you get a continuous duty!

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