LotusTalk - The Lotus Cars Community - View Single Post - HELP-Radiator fans don't turn off!!

Cinesnow · 08-17-2008, 10:45 AM

I pulled this up for your intensive learning purposes, hope it helps . . .

The two cooling fans are fitted beneath the radiator or (with a.c.) condensor/radiator package, and the coolant re-circulation pump is mounted below the header tank. Both fans and pump are controlled by the engine management ECU using data provided by the coolant temperature sensor mounted in the back of the cylender head.
The Cooling fans are switched on as a pair, and will operate at half speed (connected in series) when coolant temperature reaches 98°C/208°F on rise, and swich off at 94°C/201°F on fall. The fans will also operate at half speed irrespective of coolant temperature if the a.c. os switched on and the compressor is running. If the coolant temperature is rises to 103°C/217°F the fans will switch to full speed (connected in parallel), reverting to half spee at 98°C/208°F.
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 of the engine magement system detects a fault with the inlet air temperature or coolant temperature circuts.
At road speeds in excess of 85 mph (135 km/h), equating to fan stall speed, all fan functions are switched off.

Heat Soak
In order for the ECU to help control the engine temperature after switching off an engine whose temperature is over 88°C/190°F, the ECU will remain powered for a period of 20 minutes to allow heat soak management.
A coolant re-circulation electric pump is mounted below the coolant header tank and is plumbed into the heater supply line. When energized, the pump circulates coolant through the engine and heater system, drawing coolant back from the cylinder head, and pumping it through the heater matrix and into the heater return pipe and back into the thermostat housing. The pump functions only with the ignition off in conditions where the ECU remains live. The pump is the activated at coolant temperatures over 110°C/230°F, switching off at 100°C/212°F on fall.

Fan Control Module
The cooling fans, re-circ. pump and a.c. compressor are controlled by a relay module mounted on top of the passenger side wheelarch liner.

08-17-2008, 10:45 AM	#7 (permalink)
Cinesnow Cinesnow Join Date: Jul 2007 Location: Lake Arrowhead, Ca / Sandpoint, Id Posts: 80	I pulled this up for your intensive learning purposes, hope it helps . . . The two cooling fans are fitted beneath the radiator or (with a.c.) condensor/radiator package, and the coolant re-circulation pump is mounted below the header tank. Both fans and pump are controlled by the engine management ECU using data provided by the coolant temperature sensor mounted in the back of the cylender head. The Cooling fans are switched on as a pair, and will operate at half speed (connected in series) when coolant temperature reaches 98°C/208°F on rise, and swich off at 94°C/201°F on fall. The fans will also operate at half speed irrespective of coolant temperature if the a.c. os switched on and the compressor is running. If the coolant temperature is rises to 103°C/217°F the fans will switch to full speed (connected in parallel), reverting to half spee at 98°C/208°F. 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 of the engine magement system detects a fault with the inlet air temperature or coolant temperature circuts. At road speeds in excess of 85 mph (135 km/h), equating to fan stall speed, all fan functions are switched off. Heat Soak In order for the ECU to help control the engine temperature after switching off an engine whose temperature is over 88°C/190°F, the ECU will remain powered for a period of 20 minutes to allow heat soak management. A coolant re-circulation electric pump is mounted below the coolant header tank and is plumbed into the heater supply line. When energized, the pump circulates coolant through the engine and heater system, drawing coolant back from the cylinder head, and pumping it through the heater matrix and into the heater return pipe and back into the thermostat housing. The pump functions only with the ignition off in conditions where the ECU remains live. The pump is the activated at coolant temperatures over 110°C/230°F, switching off at 100°C/212°F on fall. Fan Control Module The cooling fans, re-circ. pump and a.c. compressor are controlled by a relay module mounted on top of the passenger side wheelarch liner.