Hi, my Fiat KonTiki L Chassis year 2000 has a problem, on the mains hook up all works perfectly, once unhooked no domestic power either to the lights, water pumps or fridge igniter etc. Domestic and starter batteries aok, just been into garage for a brake and chassis job but they unable to diagnose the problem as they can't get hold of a wiring diagram !! helllppp please,