dometic rm7291l not working?

On my 2005 super sirocco caravan the fridge will not operate on mains 230 v electric. The light shows for approx 50 seconds then trips the circuit breaker On gas the light is on but cooling is very ineffective.The 12v light used to only come on with the tow car connected and engine running but now is on as soon as the car is connected to the caravan without the engine running Is it an element which has packed in or a replacement PCB that is required I welcome any suggestion