Set meter for AC volts. If there is a voltage range setting make sure you select something above 120 volts. Set the fridge on AC and then put your meter leads across the AC heating element. You may have to look at a parts breakdown to see where that element is.
If you read 120 volts across the heating element and it is not heating, meaning the fridge is not cooling on AC, then the heating element is bad. If you do not read 120 volts there check the outlet that the fridge is plugged into. If you have the voltage there and the cord is plugged in solidly, chances are you have a fridge controller failure. This could be the board or a relay, if used, or whatever.
If there is no power at the outlet, check the circuit breakers. Reset all just to be sure.
Retired electronic technician (45 years in the field)
2017 Greyhawk 29W
solar & many other mods
wife (maybe I should have given her top billing)