Quoting Myles: The original Chris W articles are still on my site http://alcester-racing-sevens.com/chris_w_-_electrickery.htm - as is a write up of how I find it (somewhere). The switches & relays edition is what you wasn't.
Thanks Myles, I've just mocked that up using a relay and a switch that I have that has a built in LED. It seems to be working (the switch activates the fan) but there's one strange thing... The LED is ON when the switch is OFF and the LED then goes OFF when the switch is ON.
I'm using piggyback connectors on the rad switch, then wiring the relay as shown in your diagram. From there I'm connecting terminal 86 on the relay to the ON terminal on the switch. The switch then has an OFF terminal that I'm wiring to ground and also a ground terminal on the side that I'm also wiring to ground.
Please excuse me if my description is not the best, I'm not an expert when it comes to electrics.
Any ideas on how to get the light behaving correctly?