Hi Jim
Your symptoms sound similar to the ones we had in our Abbey,is the light on when on mains power, if it is you have power to the fridge and is probably the element as previously suggested, if the light is not on it is worth checking the fuses in case one has blown,we had problem where light was not working, but it was only a dirty contact, if you cannot find anything obviously wrong, I would phone Dometic, the number I have is 01582 494111, explain the problem to them and they will arrange for a mobile service engineer to inspect the fridge, we have always had ours done under warranty, but I suspect with the age of your van it will be chargeable, although I can't see it being