Fan control is accomplished in two ways.
The fan always runs when the compressor clutch is engaged.
The fan is also turned on by the temperature of the coolant which is sensed by the coolant temperature sensor. The coolant temperature sensor sends this signal to the engine controller which turns the fan on through the fan relay. Switching through the engine controller provides fan control for the following conditions:
Fan will not run when cranking engine no matter what coolant temperature is.
Fan will run when A/C clutch engaged and low pressure cutout switch is closed.
At vehicle speeds over 40 mph, fan will run only if coolant temperature reaches 230 F (110 C) and fan will turn off when temperature drops to 220 F (104 C).
At vehicle speeds under 40 mph, fan will run when coolant temperature reaches 215 F (102 C ) and fan will turn off when temperature drops 200 F (93 C).
To prevent steaming, the fan will run with engine at idle speed and only for three minutes, when ambient temperature is below 60 F (16 C) and coolant temperature is between 100-207 F (38-97 C).
NOTE: The engine coolant temperature sensor threads into the rear of the cylinder head.
With the engine cold, drain coolant until level drops below sensor.
Disconnect coolant sensor electrical connector.
Remove coolant sensor.
Install coolant sensor.
Tighten to 18 Nm (165 in lb) torque.
Attach electrical connector to sensor.
Fill cooling system.
Tuesday, August 15th, 2006 AT 7:55 PM