Description & Operation

CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See the following:

For 2002 models, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.
For 2003 models, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.
For 2004 models, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery.

Cooling fan motors operate when Powertrain Control Module (PCM) determines fan operation depending on various inputs. The PCM monitors certain parameters such as engine coolant temperature, vehicle speed, A/C on/off status, and A/C pressure to determine engine cooling fan needs. The PCM controls the fan operation through the Low Fan Control (LFC), Medium Fan Control (MFC) and High Fan Control (HFC) outputs. The fan motor operates only when the ignition switch is in the RUN position. The fan motor will not operate with the switch in the OFF position. Also operates when the A/C is turned on. Cooling fans receive power through the cooling fan relay, which when energized, directs voltage to the cooling fan motor. See WIRING DIAGRAMS .

Models with 2.0L engine, use a Cylinder Head Temperature (CHT) sensor. The CHT sensor sends the PCM a signal indicating the cylinder head temperature. CHT sensor resistance decreases as coolant temperature increases. Models with 3.0L engine, use a Engine Coolant Temperature (ECT) sensor. The ECT sensor sends the PCM a signal indicating engine temperature. ECT sensor resistance decreases as coolant temperature increases.