Battery Auxiliary Switch

Discussion in 'General RVing' started by msaele, Oct 6, 2008.

  1. msaele

    msaele New Member

    Just purchased a 2005 Rexhall American Clipper with an auxiliary battery switch that is a single pole switch that converts the coach batteries into chassis batteries for the purpose of starting the motorhome. Book says to press and hold the switch to engage the coach batteries and release the switch after the motorhome starts.

    The switch has an indicator light that is on most of the time. It is on when the home is parked and plugged in to a 110 outlet or when cruising down the road.

    My question is, should the light be on most of the time? This indicates that the coach and chassis batteries are connected most of the time.

    I would think that the light should only be on when I press the switch to connect the batteries.

    Any thoughts on this?
  2. ironart

    ironart New Member

    Re: Battery Auxiliary Switch

    Hi Marty and Welcome.....

    The switch you are referring to should be a "Momentary contact" switch.....When pressed it will activate a large solenoid switch which is located somewhere near the batteries......large cables from each battery should go to the solenoid so you can identify it....

    The light should only be on when the dash switch is pressed and should go out when released.....

    Two possible causes....1. the dash switch could be sticking closed and will not release the power going to the solenoid.......or 2. the solenoid is stuck in the "On" position..... The later is probably the problem......many times the contacts in the large solenoid get corroded or arc together causing the solenoid NOT to release when the power is removed........sometimes you can tap it with a hammer and it will release but it will probably happen again......Replace the Solenoid and you problem will probably go away.....

    Just personal experience.....
  3. Kirk

    Kirk Senior Member

    Re: Battery Auxiliary Switch

    I tend to suspect that the light in the switch might also be the problem. In my experience with electricity, I have seen very few high current contractors stick shut. They are more likely to fail open but it is possible. A very easy way to check to see if the previous post is correct would be to lift the negative cable from your chassis battery and try the chassis starter. If those contacts are stuck shut, the engine will crank. If it does nothing, then the contacts are open.

    If you do this test and the engine does not crank, you can complete the test by holding the emergency start switch down and try again. If it then cranks you will know that the solenoid does work properly. To be sure of the light issue I would need to know how it is wired. I'm not sure just what being on "most of the time" means. Apparently the light isn't on all of the time. What is happening when it isn't on and what will cause it to turn on, or off?

    Where is that light located? Is the light on the dash near the switch or is it physically in the switch it's self? I have more than 40 years of electrical service work but I still need to know more in order to be sure exactly what the problem is, or if you have one.
  4. Guest

    Guest Guest

    Re: Battery Auxiliary Switch

    well not to doubt Kirk's reply ,, mine stays lit when the runing lights and such are on ,, kinda like the gauges ,, it also dims with the dash light control ,, but i think kirk might be on to something ,, JMO ,, and welcome to the forums :approve:
  5. Paul235

    Paul235 New Member

    Re: Battery Auxiliary Switch


    Can't this relay/contactor also be closed automatically when the coach is plugged in to shore power or the engine is running to charge all batteries? Although I haven't traced it out in my coach, this is how it acts. I assumed this would be a simple way to isolate the battery circuits. I know you've had lots of expierience with this stuff so I would appreciate your thoughts.
  6. msaele

    msaele New Member

    Re: Battery Auxiliary Switch

    Thanks all for your input. I contacted Rexhall service dept and they said that it is normal for the light (which is located in the dash mounted switch) to be on. The only time I have seen it go off is just after I start the motorhome.

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