Dave, When we bought our C-28 last June ('21) I inquired to the fridge factory about adding a switch. For the 12 volt version which is standard, you just pull the fridge out and cut the Positive/+ DC wire to the fridge and add a switch. (Extend the wire to wherever you want the switch).
It's somewhat difficult to assure the the fridge is really OFF. The internal wheel thermostat will do that but if you leave the door open to keep mold from growing, on ours, the LED inside light stayed ON which can slowly drain the battery over a long period of time.
As noted, just pull that 15 amp fuse behind the helm, tape the fuse to the compartment door with a note of what that fuse is used for and where it is supposed to go. We just did that. We will use a simple cooler for our day trips and turn it back ON if needed for longer trips.
Bob/Bradenton
PS: I downloaded the full C-28 manual and color printed the Fuse box locations/diagrams (and schematics too). Plastic laminated them so that we can locate the proper fuse easily. (By the way, if you do that and keep a copy in that helm fuse compartment, there is a slot toward the back of the compartment where the fuse diagram can slip down into and be gone forever. I'm going to seal that slot with spray foam since I like to keep the diagram in there for ready use).
