Ned Kelly is wrong! that's way way back when caravans did not have on board 12volt system and I assume you'rs has. It's a case of checking 12volt and Mains. But also the newer models had a system control board with car/caravan switch giving you the option to run the 12 volt system from the car in the event of a leasure battery failure, but I wouldn't advise this as a long term service or you'll end up with a flat car battery.
You need to test the 12volt circuit: are the internal 12volt lights working ? yes then check the 12volt fuse feeding the fridge... No then check your leasure battery condition and fees to various units on 12volt.
Mains: Purchase a Continuity plug which has 3 neaon lights and when plugged in to a socket all three should light up of circuit functioning correctly. Pull the fridge mains plug and test the socket that plug was in. NO current...........disconnected somewhere. Check the main MCB switch has not tripped,check the 10amp [sockets]and 5amp [lights]
Turn mains off or remove site cable before poking fingers around sockets etc to see if cables are fixed properly and securely.
Check the mains site lead is working satifactory which if current reaching caravan for internal mains lights then it is drawing current to the caravan. It's worth invesiting in a 'Live cable detector' Wickes around £10.00.Basically it's a check everything job, a pain I know.
Bob
August 2010