Vehicle engines are often cooled by pumping a fluid through the engine block to collect the heat and then passing the heated water through a radiator matrix through which ambient air is forced either by virtue of the vehicle's motion or by forced air from a fan. The modern style is to use an electric fan controlled by a heat sensing switch or thermostat.
Your light showning a watering can with a fan on it strongly suggests something defective with the enginine cooling system rather than anything horticultural.
Good luck..
Peccavi, June 2009
