Electric 1988 E-150 Okagagan Camper Van

You just haven't found the AC breaker panel yet. For everything to work correctly, you need to get a house battery in there. A lot of stuff needs 12 volts and your converter may not furnish it without having the load of a battery connected to it. I'd suggest 2 6 volt golf cart batteries in series as the most bang for the buck if you have the space. Every converter I've seen has had a built in battery charger although the new ones have much better chargers in them. If it is that old, a new converter would be a good investment as the old ones tend to fail without warning. The relay you speak of in the battery compartment is most likely the 'emergency start' relay that should have a switch somewhere on the dash. It lets you start the motorhome off the house batteries should you run the chassis battery dead. It may also be a battery cutoff relay. If it is that, it would be a 'latching' relay that will hold mechanically in both on and off position. They use those so when the coach is 'turned on' you do not have a energized relay coil draining your batteries. How does the propane tank look? You may need to get it recertified at a propane dealer in order to find someone who will fill it (someone generally always will but the time you REALLY need propane is when everyone will start telling you it needs recertification). The way to sail through that process is remove it, wire brush and give it a fresh coat of paint making sure the stamped in data is clearly legible. and reinstall it with shiny new bolts. Propane dealers like stuff that looks good. Since the fridge works on electric, the cooling unit is good. You just need to move forward with getting propane to it and make sure that function works. Same with the furnace. Both need a solid 12 volt supply so batteries are the first order.