R pod battery not charging while we drive

I am no expert on electrical stuff. Our fridge was giving me a fault signal for battery too low. We had been driving 3 hi hours and had selected battery for fridge power. Apparently this drew down the r pod batt. I have have used this 2016 179 for three years with many long trips and it always seemed like the charging system worked. I did see that I was able to add charge to the batt the other day while using our solar panel. Might a fuse somewhere be blown? The tow lights work so the trailer is getting power from our truck. I am not sure what's up..insights?

The best way to check if it is tow vehicle or pod battery related is Using a volt meter. If you look at the plug on your tow vehicle, place one meter lead at the "one o'clock" position contact, and the other at the "seven o'clock" position contact. It should read somewhere around 13.8 - 14.2 DC volts if it's working (the car should be running). If it doesn't read that, the problem is the tow vehicle isnt putting out power. If the reading is correct, then check the battery with the meter. if thats good, look for the inline fuses, then the converter box. All though i doubt it is this, check both GFI switches for a fault (i think you have 2). If you have no DC power at all (do the lights work) it might be the 40 amp fuse.