Calais V6-3300 3.3L MFI VIN N (1990)
Radiator Cooling Fan Motor: Description and Operation
The coolant fan is controlled by the coolant fan relay. The coolant fan relay is electrically operated by the ECM. The ECM receives input signals from
the coolant temperature sensor, the vehicle speed sensor and the A/C mode selector. The ECM activates the coolant fan relay when the engine coolant,
which is sensed by the coolant temperature sensor, is above 227°F, when the A/C is turned on or when the coolant temperature sensor fails. Any of these
input signals causes the ECM to ground circuit 335 when vehicle speed is less than 35 mph. With circuit 335 grounded, the coolant fan relay is energized
and its contacts close, turning the coolant fan on.
