12 volt circuit breaker tripping

[Leyland]

I have a 2017 Montana 3791 RD and have the 12 volt circuit breaker tripping and resetting. It is not the one going to the hydraulic pump. This is the one that feeds other 12 volt stuff in the unit. I have narrowed it down to one red wire. I disconnected it from the breaker and no more problem that I can tell with the exception the furnace will not come on. I have turn off the switch. At the furnace and it still open and closes when the red wire is connected. Don’t really need furnace here in Georgia right now but need to get it fixed soon. I replaced the little circuit breaker and it still tripping / resetting when the red wire is connected. I don’t know where this wire goes . I checked the panel box and don’t see a red wire on the fuse link for the furnace. Need advice ….
Sorry for the long post but wanted to let you
All know what I have done and narrowed it down to.
Open for suggestions …. Thanks

[rohrmann]

The way most of them are set up is, the positive wire comes off the battery and goes to either one of the breakers on the back wall of the battery area. It then jumpers over to the other breaker. One of the breakers have several small wires coming off of it, going to the propane detector, the hydraulic control panel, and several other things. Coming off the other breaker, there are usually two wires, color doesn't matter, and one goes to the hydraulic pump motor via the reversing switch, and the other disappears but is going to the battery disconnect switch, usually in the convenience center. From that switch, that wire goes to the 12 volt side of your inside electric panel.


A lot of power goes through that breaker, both directions, but when setting up or breaking down, your hydraulic motor is working hard and many times is exceeding the amp rating of the factory installed breaker, which has been a 50 amp breaker. The fix for that is to follow the recommendation of Lippert, the people who made and designed the system, to install an 80 amp breaker.


This is a photo of what I have in our rig now. Where the new 80 amp breaker is was the same breaker that is on the right, and the jumper between them is connected to the incoming side of both breakers. The reason both large wires can be connected to the load side of the 80 amp breaker is that you aren't operating things inside the rig when setting up and extending the slides and jacks. Once set up, then you are inside, running the various things on the 12 volt side. A photo of what you have in your rig would be very helpful to help you figure out what is happening with your setup.

[BB_TX]

Makes no sense to me why they use auto resetting circuit breakers on circuits that are continuously energized. Auto reset breaker for the hydraulic pump ok since it is only energized intermittently when running the pump. For the breaker for the rest of the trailer there are circuits that can be on continuously. And if there is a short, or something drawing too much current, that breaker will keep trying to energize that bad circuit until something gives. Maybe burning wires.

I would not replace that breaker with a higher amp breaker. Too much risk of burning something up. Again, ok for pump, but not the other(s).

I have no idea where those miscellaneous wires go. But if you can’t isolate the problem, have someone experienced in that wiring repair it for you.

[rohrmann]

The breaker that feeds the hydraulic pump can be a manual or auto reset style. I installed the manual reset 80 amp when I did ours. These automotive 40 or 50 amp breakers are cheap, so I'm pretty sure that was the driving force behind there use. The wiring that goes to the pump and to the inside panel is #4 strand copper which is more than capable to handle the 80 amp breaker and this is the size breaker Lippert says should be used. This Lip Sheet applies to all Lippert hydraulic systems, regardless of brand of RV. Notice, Lippert does not specify the use of a manual or auto reset breaker. This has been an ongoing problem for years. I found the original Lip Sheet in 2013, and was having the problem back then. I bought the breaker and installed it and haven't had an issue with intermittent hydraulic operation ever since.

https://manuals.heartlandowners.org/...ippert0058.pdf

[Leyland]

Storming here tonight and couldn’t get a picture. It is not the 80 amp breaker feeding the hyd pump . It’s the 30 amp cheap breaker that feeds to rest of the camper. I have it narrowed down to one small red wire that must feed the furnace. I unhooked it and the breaker doesn’t continuously close and open. Everything in the camper works except the furnace. Now to find out where the red wire is shorted to ground. I replace the breaker to ensure it’s a good one. Still open for suggestions

[BB_TX]

Possible that wire has rubbed thru the insulation on some metal edge or a screw somewhere after it disappears from view. Would have thought the furnace 12 vdc wiring would be from the fuse panel. But obviously the wire is somehow associated with it. You may have to open up whatever panels you can to access the furnace wiring and see if you can find a red wire there.

[Leyland]

Thanks BB TX. That’s what I was thinking as far as trouble shooting goes. I think there are two 12 volt feeds to the furnace, one for the controls and one for the fan. The reason I say that is with the wire unhooked I still have 12 volts at the fuse panel inside. The fan will not run. I can leave the red wire connected as the breaker constantly open closes Just for a split second and then opens again. Will see if I can find where it’s shorting out later this week when storms pass.

[BB_TX]

That’s why I keep saying it seems to me to be a misapplication of an auto reset circuit breaker. Just keeping tripping and resetting that breaker and hitting that wire with over current and that short is going to keep heating up.

Once you solve the problem you probably should replace the breaker again. Each time it trips it burns the contacts a little and makes it more prone to trip.

[Carl n Susan]

Originally Posted by Leyland

....It is not the 80 amp breaker feeding the hyd pump . It’s the 30 amp cheap breaker that feeds to rest of the camper....

As Bob pointed out the 6 ga. wire from the 80 amp breaker (the left one) feeds the fuse panel. The other self resetting CB should be a 50 amp on a 2017 model.

I have it narrowed down to one small red wire that must feed the furnace. I unhooked it and the breaker doesn’t continuously close and open. Everything in the camper works except the furnace. Now to find out where the red wire is shorted to ground. I replace the breaker to ensure it’s a good one. Still open for suggestions

The lack of a wiring chart has been an issue for a long time. We think we know what those small wires from the 50 amp breaker (the one on the right) feed but AFAIK no one has ever traced each and every one.

I though the Montana 12V Wiring Color Code would help identify the wires. https://www.montanaowners.com/forums...?do=file&id=39 But there is no mention of the furnace in that document. How can that be? It uses 12V, it needs to have a wire to provide it, and that wire has a color. Color me confused.

Good luck on figuring out what the red 12V wire from the right 50 amp CB actually does.

[RicknTee]

You could run a wire from breaker to furnace and connect it, disconnecting original wire, this will tell you if it's a store issue or your furnace.