AUX battery button not working

[Mongobird]

I bought a spare several years ago, and have not needed it, but I recall that the solenoid came with standard contacts and silvered contacts. The latter are presumably longer life. I think the price was something like $30 and $40.

[Morich]

Originally Posted by Mongobird

I bought a spare several years ago, and have not needed it, but I recall that the solenoid came with standard contacts and silvered contacts. The latter are presumably longer life. I think the price was something like $30 and $40.

Yes, this is a very common question an dlots of different answers so we have to do some sorting just as anything we find on the internet.

This is one "funny" that I might want to look over VERY carefully before deciding to go with this advise!



I walked out to the back and turned off the irrigation but when I got to the RV, it still wouldn't start. Do you think I have a bad solenoid?

[Sk8Surfr]

So - I bought the attached - hooked it up - and did not work! Is this the wrong one? Cole Hersee 24115

I bench tested - applied 12 v to the small center stud - left one large one open - NO power to the other large stud....

I also bought a cheaper off brand solenoid on amazon - that clicks - and I get the voltage to the other stud. But I don't think it's rated for continuous duty - so I was not going to use it...

[Morich]

Sorry , that looks like wrong type solenoid as the 12 power for the coil needs to come down through the coil and go to ground. Usually on the three lug type used on RV, that gets connected to the metal case and that case is screwed to metal frame to make the path to ground.

This drawing shows the small lug is connected to the big side lug where we put one of the battery cables so no good.

I have not changed one of these in a long time and don't know the right model number.

Any of you other folks out there have that model number in mind?

[Sk8Surfr]

So the other one I bought on Amazon was - https://www.amazon.com/dp/B0797WZBD9...t_details&th=1

The PN on the one I removed says
Camdec 97226-WR 12V/CONT

Google shows Winnebago PN 008188-01-000

[Sk8Surfr]

I'm thinking that Amazon one will not work - because when the RV is running I'm getting 12v power to the center stud - which will activate the solenoid and probably fry it?

[tim myers]

Actually when when the engine is running the solenoid should be engaged, That is how the alternator charges your house batteries. I know there are variations of operation among different Mfg's and Mdl's but mine is engaged when the engine is running, disengaged when starting unless you push the Battery Boost Switch. Some relays have an isolated ground and have two wires running to the coil while some ground through the attachment point and have one wire running to the coil.

[Morich]

If I remember correctly, there is a Cole-Hershey continuous duty with silver contacts which seemed to be favored. In his RV they have the three wire model which uses the small wire from the front to send power to the coil and uses the mounting for ground.
Other models of Winnebago use a second wire to also provide ground and a four post solenoid.

Do the silver coated contacts last longer? I don't know as I know silver melts at apretty low temp and these are used in continuous duty making heat a question.

For my use, I have never specified silver as they are an item which last ten years or more and I have never had to replace one twice on the same RV. did they last longer? Only the folks who bought the RV from me would know!

But if others feel better with the silver contacts, I have no reason to question their choice, either. When dealing in the $25-50 range, I don't spend a lot of time debating something that I may never look at again!

[tderonne]

I think Trombetta is the supplier you're thinking of regarding silver contacts. Been discussed here many times.

And I don't think I'd ever rely on the solenoid and wiring to it to start the engine without a chassis battery in place. The solenoid and wiring to it aren't rated for that kind of amp draw. I think that may be a contributor to the many dead solenoids that folks have.

[Morich]

Agree that trying to use the solenoid to start the engine is not going to be easy if there is no chassis battery! First big problem to work around would be that the chassis battery needs at least some power to pull the solenoid. No power to wire LR gets you no solenoid operating and that leaves you nowhere good.

But if we really NEED to get the engine started, it would seem fine to just short the big cable from the coach batteries to the big cable on the other side of the solenoid. No difference in the cables sizes of both so if we can't get the solenoid to work, extending the coach cable to the chassis cable is what the solenoid normally does for us.

Very much the same as using a different car to get a boost except when using a second car we have to use both positive and ground cables to get the grounds combined.

What solenoid is best is often like other things and what we each consider worthwhile. There are often recommendations for using the Cole-Hersee 24213 but that model has the four lugs and would need a slight mod to use it on THIS Rv . Looking at what that model does with the fourth lug is not rocket science if we know a circuit has to have a full circuit (circle?) to operate.

The three lug verstion of this solenoid gets power on a small wire that Winnebago cals "LR". That power goes through the coil and gets to ground using the metal of the solenoid and the mounting to the frame as ground.
This is the diagram for the model 24213 which has four lugs, so a little bit of thought can let us use this one, too.



The power we get on lug two has to have a path to ground to operate. The RV which use this four lug version provide a seond small wire with ground to the second small lug. That completes the circuit and it works!

So if we really want to use a four lug instead of a three lug, we have to figure out how to provide a path to ground, even when we don't have that second small wire!
So how about just putting a small wire on that last little lug and running it to the mounting screw for ground?

Not the way I would prefer to work it as the four lug is often more expensive and I don't need to spend extra time and effort to run my own ground.
But if I have or can get a four wire solenoid but not the three lug version, I'm okay with doing what makes it work!

[eyecando]

The best way to test the solenoid is to first verify you see 12+ volts at the small terminal reference ground (or between the two terminals if you have two) with the button depressed. Once that has been verified, place the multimeter set on volts with one wire on each of the large terminals. You will read the difference in volts between the two terminals of a few volts. Once the button is depressed to tie the banks together, the multimeter reading should drop to probably less than 0.2volts if the solenoid is good.