Where is the battery isolator solonoid?

[Lukeaa]

My alternator has suddenly stopped charging my house batteries. Research indicated it may be a problem with my battery isolator solonoid. Does anyone know where that might be found on my 2007 Diplomat?

Thanks,
Luke

Arriving in Quartzsite on January 2nd.

[texnet]

Not sure on a 07 Diplomat, but maybe info on my coach will help until someone else post about your coach.

My coach does not use a solonoid, but uses a solid state isolator which is located in the right hand (looking at the engine) electrical box in the engine compartment. The alternator goes to the center post, the top post goes to one set of batteries and the bottom post goes to the other set of batteries.

[itdave]

Hi Luke
On 06 Dips the ability to charge the house batteries from the alternator is done using the same solenoid that is activated by the Battery Boast switch. The solenoid is located on the back wall of the bay that holds the batteries and when energized ties the house and chassis batteries together. There is a circuit board located in the front run bay that senses when the Chassis batteries have reached a sufficient level and then energizes the battery boast solenoid. This allows the alternator to charge the house batteries. I am not sure about the 07 Dip because at some point Monaco replaced the on way circuit board with a bidirectional circuit that allow the chassis batteries to be charged while the coach was connected to shore power or the generator was running.
I think you can check on the solenoid by engaging the battery boast switch and listening to the solenoid. I think there have been discussions about the contacts inside the solenoid failing so that could be the problem or the maybe the circuit board is not telling the solenoid to engage. One way to check to see if the solenoid is to measure the voltage on the house and chassis batteries then engaging the boast switch and see if the voltages match once the solenoid is engaged.

[Lukeaa]

Dave,

Thanks for the help. See you in Quartzsite.

Luke

[Monacoach]

couple more tid bits for you....... feel the solenoid, it should not be hot to the touch.............. when applying booster switch and you hear the solenoid click, that does not mean it is functioning............... there will be two battery cables and two small wires connected to the solenoid, check to see if there is power at one of the small wires........ after coach sits for a while ( not connected to shore power or engine running) there should be no power at the small wire. If there is power, that means your circuit at front of the coach has malfunctioned and has burned out the solenoid.............. this is from my personal experience... I have changed my solanoid 3 times......

[dogpatch]

In my coach, that solinoid is located behind the panel in the steps. My batteries are located under the steps to the RV. Your configuration may be different, but the solinoids are usually in close proximity in any case.

[Lukeaa]

After pulling out the multimeter, there is no power to the two smaller wires. So I will assume that the circut board up front is still good. There is no power going throught it when the boost switch is pushed, so I will say the 12v DC contactor has died, which sounds like something that happens fairly often. I have ordered a new one from:

Trombetta 114-1211-020 DC Contactor

$43.05 plus tax and shipping. Thanks for SacsTC and Monaco Mama, for the web address of the replacement part. All of you guys/girls make maintaining an RV simple.

Next project is the rivet in the door latch.

[Robi.1014]

Luke,
On my rig, the dash "Battery Boost" switch, when depressed, only sends energizing voltage to the Trombetta solenoid for a brief period of time (after the ignition switch is turned ON). So just pressing this button at other times may not be proof that the solenoid is bad.

[Monacoach]

Did you check the fuse?

[YC1]

Quote:

Originally Posted by Lukeaa After pulling out the multimeter, there is no power to the two smaller wires. So I will assume that the circut board up front is still good. (No voltage at the solenoid small terminals means you do not have a control voltage and the solenoid is not being engaged)You may have to have your "salesman switch",the one next to the door that turns a lot of things off, turned on or the auxillary boost switch might not work. You can hear the relay clunk if standing close to it. If it was working it could indeed be hot to the touch. These continuous duty solenoids draw about 1.5 amps which is close to a 25 watt bulb. They will get hot.There is no power going throught it when the boost switch is pushed, so I will say the 12v DC contactor has died, which sounds like something that happens fairly often. I have ordered a new one from: Trombetta 114-1211-020 DC Contactor $43.05 plus tax and shipping. Thanks for SacsTC and Monaco Mama, for the web address of the replacement part. All of you guys/girls make maintaining an RV simple. Next project is the rivet in the door latch.

In any case a new one is a good idea because as mentioned they are a frequent failure item. I may have discovered why and will share that in a moment.If your large solenoid has a violet wire that should be the one that gets 12 volts applied to it. The other wire, probably black, is the ground. If you want to do a simple test, grab a piece of wire and connect a 5 amp fuse to it. Then touch one of the large terminals on the solenoid and the other end to the violet wire. The solenoid should go clunk.I have an 08 HR Endeavor and all the wiring diagrams and schematics.

[YC1]

I will post pictures and schematics but get irritated when I spend 30 minutes typing and the thing goes hay wire.

As for the reason I think those solenoids fail. First let me premise this with the fact that I own a repair business that has replaced thousands of relays and solenoids in vehicles in the last 35 years. We do installations on cop cars, ambulances etc and can troubleshoot a relay problem in less than 30 seconds once we find it.

That continuous duty solenoid runs very hot and is mounted with the terminals on the top. After taking two of them apart and seeing pictures of others with the same problem I believe that the heating and cooling of the solenoid pulls in tiny bits of moistuer. That moisture cannot get out and you end up with green gooey contacts inside that are easily cleaned and put back in service if you have a solder gun.

When I overhauled my third solenoid last month I mounted it with the large terminals pointing downward. At least any moisture will likely get pushed out instead of puddling up inside.

[YC1]

I see this issue so often on the forums I have set up a folder with all the pertinent information.
(This is a note I have left for myself as a reminder)
This folder has several pdfs copied from various places in my files. I copied them to one folder so I can send helpful information when needed and don’t have to search all over the place.

[YC1]

More files.

[YC1]

If the battery boost button is not working, and the "bird system" is not working, then I would look for a blown fuse in the front run panel below the driver in the outside compartment in the large box. Look for F58 or anything that says auxilary power or something of that nature.

I do realize our schematics and electronics may not be identical but have found these pictures and diagrams to be very useful in any case.