12v system not working, R-POD 180

I've done some Googling and haven't figured this out yet. 2 6v batteries in series, they've been on trickle charge over the winter. Hooked up to my 180 and none of the 12v system works (lights, hitch lift, etc).  If I plug in our vehicle via the hitch power hookup, everything works like a charm. If I plug into shore power, everything works great.  Just not with the batteries. If I multimeter the batteries their combined voltage is 12.7, so they should be ok.  If I check for voltage at the solar hookup on the side, it's 0.  I know they talk about manual reset boxes under the frame that the 12v system goes through. Looking around I can't find manual resets (with the little black button). I see a gang of three little grey boxes underneath near the front with the red leads going through them, but none of them have reset buttons. I looked and felt around on them. Just for grins I stuck my multimeter on the various nuts of the little boxes and was getting voltage.

Thanks for the reply!  Cut off switch is turned on.  Batteries are connected correctly, negative on first connected to positive on second, black lead to second battery negative and positive lead to first battery positive.  I checked the two 40A fuses in the panel and they looked fine.  If the fuses had blown, wouldn't nothing get power from the car connection at the hitch?  My confusion is that I get 12v power from the car hitch connection and from the shore power (from the converter I assume) so the fuse bays would be good. I reset all the circuit breakers in the panel just to be sure, and made sure the gfi was set, but that's 110v not 12v.

On mine when I had the dual 6V batteries connected, I had Red to positive lead on first battery. Jumper negative on first battery to positive on second battery. White to negative on second battery. No issues with it. I agree that you should check your battery connections and make sure they are not corroded and are tight. I am assuming you did check the electrolyte level in the batteries and topped it off with distilled water as needed.

Could have been a slightly corroded connection for the fuse. In any case, I am glad things are working. Keep in mind the cut-off switch. I have heard of them going bad, especially the ones with the removable key. If you look in my mods, you will see the type I got. It has been reliable with no issues. I can't say the same for some of the other types. I have heard of them going bad.

I fixed it by taking out the 40A fuses and putting them back in!  I wish I could say I did something technical or stumbled across the magic fix, but it was as simple as that and I just assume it wasn't seated properly or was a little corroded or something.