autocruise colt electrics

My Autocruise Colt has developped an electrical fault. The steps no longer retract when the engine is running, and the fridge makes a strange rattling noise when switched to 12v. According to the manual, there are some relays that should operate when the engine is running. Does anyone know where they are ? And where is the relay for the steps ?    I suspect a broken wire somewhere because the trouble started after I had some work done. The first time it happened the steps retracted a couple of minutes after the engine started instead of immediately' but now it always has to be retracted manually. Because of the noise it makes I don't run the fridge on 12v any more, which is a nuisance.