Since nobody has replied, I’ll take a stab at it. My boat is a 2012 R27. I’m going to start at the house batteries and work forward. Please don’t take the simple nature as a question of your abilities.
1) House battery switch ON. Check that house battery voltage is sufficient to start refrigerator.
2) Under the battery switches right next to the floor in that compartment is a polygon shaped flat breaker that supplies power to the DC power panel at the helm. To get an idea of what you’re looking for, the breaker in question looks just like the windlass breaker at the helm. A lot of DC powered electrical items will be inop if that breaker is tripped, so if that’s NOT the case, it’s probably not tripped. The refrigerator on my boat is one item that gets power through that breaker. Your boat may be the same.
If the breaker IS tripped, a small lever protrudes at an angle from the bottom of the center portion of the breaker. On my boat, that lever is black and very easy to miss. On later model boats I’ve seen, it’s red or yellow and it stands out much better. To reset the breaker, flip the small lever back up flush with the center portion of the breaker. There is a red TEST button in the middle of the breaker. THAT IS NOT A BREAKER RESET BUTTON.
3) After assuring the breaker under the battery switches is not tripped, at the helm DC power panel, turn the refrigerator breaker switch ON. A green light next to the breaker switch should illuminate. If that green light does not illuminate, you may have a bad breaker. I’m not 100% sure of that last statement. If someone reading this knows for sure, please respond with a clarification.
4) If the green light at the refrigerator breaker/switch is illuminated, the next thing to do is to pull the refrigerator out and check for power at the connector to the refrigerator.
To remove the refrigerator, first remove the door and set it aside. Next remove the four sheetmetal screws at each corner of the refrigerator frame that are driven into the fiberglass surrounding the refrigerator opening. That is a truly awful way to secure the refrigerator, but that’s how they did it on my boat. If your boat is like mine, there is no support under refrigerator inside the opening. When removing the screws, remove the top two first and then the bottom two. When the bottom screws are removed, the bottom of the refrigerator will swing out a couple inches. It’s my understanding that on later model boats, support was put under the refrigerator so hopefully yours is a late enough model. I modified my boat to provide support under the refrigerator.
5) Pull the refrigerator out. There is enough slack in the wiring supplying power and ground to the refrigerator to fully pull it out. With the door off, there is just enough room to set in on the floor between the refrigerator opening and the structure on which the port companion seat and table rest. In the slack of the wiring at the back of the refrigerator, you will find a two prong connector. Pull it apart and check the power panel side of the connector for voltage using a multimeter. If the voltage measured is the same voltage as the house batteries, then the refrigerator has a problem.
Good luck!
