That fridge controls will continue to function down to 9.6V DC.
There are 2 fuses on the lower control board
A 3A ......DC Controls (which is OK cause you have display/functions)
A 5A ......AC Heater (which is OK if you can place in 'Auto' with 120V AC and it operates electric)
How long has fridge been on?
When FIRST turned on it will take 12 hrs to cool down.
First freezer compartment has to get COLD before food compartment can BEGIN cooling down.
IF it has been ON for over 12 hrs and freezer is NOT COLD/food compartment is not cooling down then you have an issue (Ventilation, air flow obstruction, bad cooling unit....items that affect BOTH heat sources)
Otherwise
Patience!