Your 3-way fridge needs to have 12 vdc power for the control board, even if you are on 120 vac shore power or running it on Propane. Also, all the lights in the trailer are 12vdc as well, so I'd check the 12 vdc fuses, and go outside and open the battery enclosure to make sure that it is wired correctly, (Black wire is power and White & Green wires go to the negative terminal. Also check to see that any battery cut-off isolation switch is on, (if you have one.). I'd also check to make sure that the 120 vac circuit breaker for the fridge isn't tripped as well. If it is tripped, it must be reset by going fully to the off position until it clicks, then back to on. Just going from "tripped" to the on position will not reset it. I would also check your 12 vdc fuse in the converter for the fridge as well to be sure it isn't blown. Also, push the fridge selector button to OFF on the top fridge control panel, and then back on to either ac or propane. Sometimes this will clear a fault condition. The fridge will only work if it has 12 vdc power for any of the cooling methods you select.
As a side note, if they disconnected the battery wires, and inadvertently hooked them up wrong, you can count on blowing the two 30 Amp dc fuses in the converter. If they are blown, they will need to be replaced. Just trying to cover several bags here for troubleshooting. Start with the simple things first.
Edited by Euphoria, 07 June 2019 - 06:22 PM.