Battery switch

[dcs500]

My battery switch is a spring loaded rocker. When I push it at the top, it's supposed to disconnect the batteries and spring back with the light going out. It wont spring back to the down position unless I manually push it down and the light stays on as the batteries also stay connected. I check the voltage at the solinoid, or cut off relay, in the battery compartment and the small connectors on the front show 12.6 volts for one second when the switch is pushed up and then they show 0 volts after one second. The main cables on each side show no voltage when the switch is activated and no voltage when the switch is not activated. Any experience with this? Pics included below. The solinoid clicks when the switch is pushed up or down.

 

[JimD]

If it won't spring back maybe a WD40 spray will loosen it up. If that doesn't work or there simply is no spring action, the switch needs to be replaced. Odds are the switch is bad.

This switch provides a momentary pulse to the relay/solenoid. According to the Jayco manual, if you press for more than a second or so you can disable the relay/solenoid requiring disconnecting the negative battery cable to reset.

 

[dcs500]

Battery Switch

Just tried the WD 40 and it worked for the switch springing back, the relay clicks yet the batteries still remain connected.

 

[JimD]

I've been trying to find that rocker switch online with no luck. do you have a link for it, or a parts store? Just tried the WD 40 and it worked for the switch springing back, the relay clicks yet the batteries still remain connected.

My electronic sources of choice are Mouser Electronics and Digi-Key. Have bought from them many times over the years. Here are links:

https://www.mouser.com/

https://www.digikey.com/

I did a quick search on Mouser and see some switches that look like what you need. Do a search for "momentary rocker switch" and see what pops up. You may have to take measurements to get the exact fit.

I tried the same search on good old Amazon but didn't see anything on the first page. You can search there too.

 

[JimD]

Just tried the WD 40 and it worked for the switch springing back, the relay clicks yet the batteries still remain connected.

Try disconnecting the negative battery cable briefly. Here is the Jayco quote:

 

[dcs500]

The rocker switch works now after the WD 40 and the relay clicks but it stays closed. I tried removing the main negative wire for one minute and no reset. I think I need to replace the relay. Any other thoughts?

 

[JimD]

Sounds right to me since the relay is "clicking". Is there any way to squirt WD40 into the relay? That stuff works wonders and you have nothing to lose at this point.

 

[dcs500]

Tried that, didn't work.
Clicks but relay stays closed. Thanks

 

[dcs500]

I don't see a way to get WD 40 into the relay. I tried banging on it like the starter solenoid on my old cars but still nothing. I'll keep trying. I found a relay online for $59.00.

 

[craigav]

It is hard to know the exact specifics for any RV as they can be (and are) wired differently based on each model and model year. Here are some bullet points to consider based on what you have stated already. It may be of value to obtain a wiring diagram specific for your RV.

1. The fact that the light stays on next to the disconnect switch doesn't mean necessarily that the switch or relay is bad, it simply means that there is power at the indicator light.
2. The light itself could be getting power from another source such as the shore power's converter (so unplug the RV while testing) or even backfeeding from the chassis battery (so you may need to disconnect that as well while testing).
3. The switch itself is likely still good, as if you hear a click when pressing in either direction, that indicates the switch is working.
4. When you measured the voltage at the solenoid and found no voltage with the switch activated and also no voltage when the switch was not activated indicates a high likelihood that you were not measuring the voltage correctly (from the correct locations in particular the black lead on the ground or battery negative). You should use your voltage meter on the battery first and make sure you read voltage, then keep the black (neg) voltage meter lead on the neg battery terminal and then the red lead on either side of the solenoid. At least one of the terminals should indicate voltage even if the solenoid is bad. Ideally one would have voltage with the solenoid off and both terminals should have voltage with the solenoid on. But as above, the voltage could originate from elsewhere which certainly would cause confusion.
5. The battery disconnect solenoid on most RV's doesn't actually disconnect all of the 12v power from the battery (which causes further diagnostic confusion) as the power from the two fuses at the solenoid is always on with the solenoid off or on and often supplies power to items such as the CO detector, perhaps the refrigerator as well. Hard to know what all without a schematic.

Just thoughts to share, probably what I would suggest to test first (and again) is the voltage at either side of the solenoid's large terminals again as mentioned above and if the RV is plugged into shore power, unplug it prior to checking the voltage. If you are not getting voltage from either terminal then that needs to be determined why before moving forward as again, even if the switch or solenoid doesn't work, you should at minimum have voltage on the battery side of the disconnect solenoid. ~CA

 

[dcs500]

Thanks for that perspective. I did measure the voltage on each side of the relay again, only I did it correctly this time and discovered that there is continuity between the 2 main cables. I checked each connection with the positive meter probe and the negative to the battery negative. !2.6 volts from each. Shows that the relay is closed. So I believe that the rod that activates up and down in the relay has broken away from the contact points which open and close as the rod activates up or down. So I'm thinking of ordering a new switch that Rustynuts found for $59 and change. Thanks

 

[craigav]

New Solenoid (or switch)? In any case, it is not a bad idea to replace the solenoid as it has a highest likelihood of being bad based on what you described.

I prefer whenever possible to verify something is bad prior to replacement however, I don't always do that. One way to test it is to remove the cable on the side with one cable (which would be the side I suspect could be backfeeding voltage), but you should have all the power disconnected prior to removing the cable to protect all of the wiring and components (as you would also want to do when replacing the solenoid).

Disconnect the battery(s), shore power, solar if you have it, and the chassis battery as well. Then check for continuity across the two larger terminals, either the solenoid will be open or closed, then reconnect the battery(s) and flip with battery disconnect switch inside and disconnect the battery(s) again and whatever state the solenoid was in (open or closed) it should be opposite... or just go ahead and replace it and if you still have an issue, you will at least have a spare solenoid. ~CA

 

[dcs500]

Great minds think alike. I did just that and the cables posts have continuity which like you said means the relay is closed. Then reversing the test, still closed. Thanks, I just ordered the spare and even though I usually leave the coach powered up, I may have to do some more maintenance of the bats, etc in the future, I'll need to disconnect. I'm in my mohome about 7 months of the year. Cheers and safe travels

 

[craigav]

Good deal, let us know how it works out after replacement. Just another thought to share, solenoids like this can last a very long time, one thing that is not too uncommon is for the contacts to weld themselves closed which occurs often when there is a large load on the circuit whenever switching the solenoid. Not that this is the only reason of course, but I would suggest to turn off everything you can 12v (such as inverters and high draw items, even the converter) prior to switching the battery disconnect solenoid. ~CA

 

[dcs500]

Got it, thanks. I'll post results

 

[Johnynorthland]

Yup, I know someone that did that, instead of holding their awning out switch they held the coach disconnect down. He Just had to disconnect the battery like you stated. For the life of me I can’t understand why they put a 12 V solenoid switch. I’d rather see just a mechanical on/off device with a light indicator.

 

[DonLegg]

They use a solenoid switch because it is built to carry the entire load of the 12 volt system (except CO detector), whereas the rocker switch is not.

 

[Johnynorthland]

They use a solenoid switch because it is built to carry the entire load of the 12 volt system (except CO detector), whereas the rocker switch is not.

I would much prefer a battery on/off switch!

 

[dcs500]

I replaced the solenoid and guess what? Nothing changed. Both cables on the right and left side of the solenoid have power. even when disconnected. So I'm guessing that there is a back feed going on but I have no Idea where from. At this point, I'm going to install a manual cut off switch in the battery compartment. When I disconnect the main positive cables, the battery system shuts down. I rarely ever shut down the system as I spend a lot of time in the mo home. 7 months or so a year. When not on the road, I leave the batteries on and the coach plugged into my 50 amp house power source. The problem occurred before I changed to Lithium so I have no clue how a back feed condition happened. One way or another, I should be okay with a manual shut off switch. I will leave the solenoid hooked up as there are other smaller wires that may be essential for CO detector or refer, etc. Any thoughts? Thanks

 

[Johnynorthland]

Takeoff the cable that you think it’s back-feeding the solenoid, clip a test light onto it and then ground the other end of the test light to a chassis ground. If it lights up, you definitely have a back feed. You could use a meter and do the same thing. Maybe there’s a slight chance That your switch is the problem, causing the relay to constantly engage. Either that or you got a bad relay.

You can check the relay just disconnected it from the battery and put 12 V to the side that triggers the relay. It should clunk and engage.