Cooling Fan Control

Underhood Electrical Center Relays And Fuses:

DESCRIPTION
The engine is equipped with two Powertrain Control Module (PCM) controlled electric cooling fan(s). The secondary fan (# 2) is used for heavy duty cooling with A/C.

OPERATION
Primary fan (#1) will be "ON" with any of the following criteria:

^ Engine Coolant Temperature (ECT) sensor signal indicating a temperature greater than 108°C (226°F) with A/C "OFF," 106°C (223°F) with A/C "ON."
^ A/C is requested and vehicle speed less than 50 mph (81 km/h).
^ A/C refrigerant pressure sensor is "open" [pressure greater than 1275 kPa (185 psi)].

OR

^ When a Diagnostic Trouble Code (DTC) 14, 15 or 70 is set. OR
^ When PCM is in back-up mode.

SECONDARY FAN
Secondary fan (# 2) will be "ON" with any of the following criteria:

^ Engine Coolant Temperature (ECT) sensor signal indicating a temperature greater than 113°C (235°F) with A/C "OFF," or "ON."

OR

^ A/C is requested and vehicle speed less than 40 mph (64 km/h).
^ A/C refrigerant pressure sensor is "open" (pressure greater than 236 psi.