From Lotus service Notes;
KH.5 - RADIATOR FAN & RE-CIRC. PUMP CONTROL
The two cooling fans are fitted beneath the radiator or (with a.c.) condenser/radiator package, and the
coolant re-circulation pump is mounted below the header tank. Both the fans and pump are controlled by the
engine management ECU using data provided by the engine coolant temperature sensor mounted in the back
of the cylinder head.
The cooling fans are switched as a pair, and will operate at half speed (connected in series) when coolant
temperature reaches 98°C on rise, and switch off at 94°C on fall. The fans will also operate at half speed
irrespective of coolant temperature if the a.c. is switched on and the compressor is running. If coolant temperature
rises to 103°C, the fans will switch to full speed (connected in parallel), reverting to half speed at 98°C.
The fans will also run at half speed, unless high coolant temperature dictates otherwise, when the a.c. is
switched on and the compressor is running, or if the engine management system detects a fault with the inlet
air temperature or coolant temperature circuits.
At road speeds in excess of 85 mph (135 km/h), equating to the fan stall speed, all fan functions are
switched off.