No power when dry camping.

[Mountbaily]

Greetings Fun Finder group. Just bought 2007 Funfinder X 139.... absolutely love it! However, I can’t get any power when not plugged in to 120 or tow vehicle. The battery is charged full. The battery box on the tongue has a shut off switch with red key. I’m thinking maybe this switch is bad but I’m lost in trying to remedy this minor problem... any thoughts? Is there a battery shut off switch I’m not aware of maybe?

[Eagle]

I'm not familiar with the x 139 but my unit has a push/pull switch on the panel inside the camper with the switches for the water heater/holding tank indicator lights, etc. that must be pulled out to supply 12 volt power within the unit.

[Xerofall]

If you can upload a picture of the setup, it might help. There are a lot of different types of cut off, etc...

Check to see if the red key shut off switch is connected to the battery, it may have been disconnected at the battery post. If it's connected and you suspect the shut off is at fault, remove the shut off portion or bypass it by connecting the two wires together. Or if you have some wire and splices to reconnect it all, just do that until you can get a new shut off, if that's the way you want to go.

I have a this type of shut off that kills the connection at the battery post itself. https://www.harborfreight.com/batter...tch-97853.html
Very simple function that physically removes the connection from the battery post.

[profdant139]

There is probably also a fuse on one of the battery cables -- the fuse is often fairly close to the battery terminals. Maybe check to see if that fuse is blown?

[Mountbaily]

I am so very appreciative of this group. Thank you all for the help. It was in fact just a bad switch. Today I bought tester and the switch when on is hot on one side but not the other. I’ll try taking apart and wire brushing or just buy new switch maybe like the one so kindly recommended. I need to learn the schematics of the wiring among other things like the low point drains and winterizing routine. For now a huge thank you from Stephen n Mira.

[Xerofall]

Glad to hear you got it figured out.

[Mountbaily]

I wanted to reply directly to you with picture of the battery set up. Previous owner has the battery shut off hooked to the positive. From my research it seems it’s supposed to attach to the negative post? Also there is a 80 amp fuse on the main positive lead which broke while I was working on it today so I suppose the fuse has a safety function so I’ll replace it as I found it. By the way... I bought the shut off you recommended at harbor freight and I’m curious if you installed it on positive or negative side? Thx

[Xerofall]

My understanding was to put the cut-off on the negative side. The reason for this is because as soon as you disconnect the negative terminal there is no way you can accidentally short the battery by having something touch the positive terminal lke your wrench for exmple. If it were to make contact with any part of the vehicle without the negative being disconnected, you could cause a short in the system and a hail of sparks. (Yes, I've done it before.)

[JimboFunFinder]

Electrons (of course) do not care whether the switch is in the positive or negative lead so the only reason for a preference is to mitigate an accidental short. Cars and trucks always seem to switch the positive side.
If you do much boondocking you may want to investigate whether your deep cycle storage battery is actually being fully charged. If you rely on the tow vehicle to charge it the answer is definitely not.