Check the mfg.'s web site (or just call them). They should be able to provide it. You can quickly determine who is at fault (boat or fridge) with a voltmeter at the connections.
If its the fridge; Look under the panel or around the chasis of the unit. They will often put a wiring diagram and even a basic troublshooting pamphlet in there somewhere.
Best of luck. Electrics problems are the worst.
