Electric Cooling Fans: Operation
The dual cooling fans operate independently or can be simultaneously activated. When radiator fan operation is deemed necessary, Powertrain Control Module (PCM) provides ground for radiator low speed and high speed relay circuits. Electric cooling fans operate based on inputs to PCM. PCM bases electric radiator fan operation from the following PCM inputs: Engine Coolant Temperature (ECT) sensor, Intake Air Temperature (IAT) sensor, output speed sensor, transmission oil temperature sensor, and A/C pressure transducer electronic value for refrigerant system pressure. See COOLING FAN OPERATION (2.7L) or COOLING FAN OPERATION (3.2L & 3.5L)
table.
When A/C is not operating, electric cooling fan operation is controlled by ECT and IAT sensor signals to PCM. Electric cooling fans will operate independently of coolant temperature when A/C pressure reaches a predetermined level. Fans will not operate during engine cranking, regardless of coolant temperature.
COOLING FAN OPERATION (2.7L)
| PCM Input/Fan |
Fan On |
Fan Off |
| A/C Pressure Transducer |
| Low Speed |
210 psi (14.8 kg/cm2
) |
175 psi (12.3 kg/cm2
) |
| High Speed |
249 psi (17.5 kg/cm2 |
218 psi (15.3 kg/cm2
) |
| Engine Coolant Temperature (A/C On) |
| Low Speed |
221°F (105°C) |
216°F (102°C) |
| High Speed |
230°F (110°C) |
223°F (106°C) |
| Engine Coolant Temperature (A/C Off) |
| Low Speed |
223°F (106°C) |
216°F (102°C) |
| High Speed |
230°F (110°C) |
225°F (107°C) |
| Intake Air Temperature |
| Low Speed |
140-145°F (60-63°C) |
|
| High Speed |
153°F (67°C) |
|
| Transmission Oil Temperature |
| Low Speed |
228°F (109°C) |
220°F (104°C) |
| High Speed |
232°F (111°C) |
228°F (109°C) |
COOLING FAN OPERATION (3.2L & 3.5L)
| PCM Input/Fan |
Fan On |
Fan Off |
| A/C Pressure Transducer |
| Low Speed |
210 psi (14.8 kg/cm2
) |
175 psi (12.3 kg/cm2
) |
| High Speed |
249 psi (17.5 kg/cm2
) |
219 psi (15.4 kg/cm2
) |
| Engine Coolant Temperature |
| Low Speed |
216°F (102°C) |
210°F (99°C) |
| High Speed |
230°F (110°C) |
221°F (105°C) |
| Intake Air Temperature |
| Low Speed |
140-145°F (60-63°C) |
|
| High Speed |
153°F (67°C) |
|
| Transmission Oil Temperature |
| Low Speed |
216°F (102°C) |
208°F (98°C) |
| High Speed |
228°F (109°C) |
224°F (107°C) |