tried it today but it seems pretty random when it comes on.. started the car without heater on.. turned it on to 1 2 3 heater is on but no engine fan.. then few secs later it comes on so dont seem to matter what its switched to and it has the orange number 3 the car is X reg .. i wondered if the aircon needed charging maybe but cant work out why the engine fan would come on without the aircon.. the only reason i wondered is because even on a freezing morning it comes on first thing and must take longer for the car to warm up... and the revs drop with it on too...
thanks..