Tank monitor/Water heater/water pump issue

Have you checked your battery voltage and connections?

X2 sounds like your batter is dead.

A bad ground is my first thought.

Are you plugged into shore power or boondocking?

Shore power. Battery is dead and awaiting replacement. While hooked up to tow rig, everything works fine. Isn’t the converter supposed to supply 12v to certain things when needed... ie these items ?

It should unless the converter or a conection is bad, then it will not supply dc or charge the battery. Now you have to check the converter out put. You have ac power right? So you know power is coming into the camper?

20 year old camper, with original converter? If so, it may need to be replaced.
Check output and connections.

Converter is dead so no battery charge or lights when plugged in. Battery is dead because no converter charging it because converter is dead. Everything works when hitched up because the tow vehicle battery is supplying the 12 volts to the trailer.

Well, after digging a little deeper, looks like everything is actually in working order. Battery terminals were loose. So I tightened those down... then realized the breaker inline with the 12v wire was tripped. Reset that. After being all connected properly and hooked up to shore power for a day, battery tested 13.8v and the panel worked. Don't know if the battery will hold a charge yet... will be testing that out in coming weeks. Going to hook up a power inverter to it so I can run my residential fridge while in tow. Will disconnect shore power when I get the inverter set up and see how long the battery runs the inverter for. If we can't get a good run, at least a couple of hours, then I'll look into upgrading the battery. I'm hoping to get at least 5-6 hours of inverter/fridge run time while in tow. Maybe run larger gauge wire with some Anderson plugs to send more juice to the trailer while hooked up to tow rig.

Glad you got it sorted out.
Happy camping.