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The control board on the fridge requires full 12 volt power to operate, then controls the 120v ( AC ) and propane through relays.
Have you checked your battery power at the batteries , or your converter charger output ?
If you have good power from the converter and batteries, then remove the lower vent at the outside rear of the fridge and check for 12 volt power there power there. Most times there will be a wiring diagram attached to the rear of the fridge.
If not there may be a diagram available in the manuals for fridges in the " Files " drop box, in the , blue bar across the page under your welcome message.