Truma 3200 heater- Wiring diagram required?

I have had the heater working on gas, but cannot get any thing from electrics, have operated the switch on the wall ie to on position and rotated round dial for temperature but no green light on dial,( these controls both on same switch) is there a remote switch to turn 240 supply on? This is fitted in a Fleetwood -Colchester caravan

J R Wild
May 2011