The primary cooling fan operates when engine coolant temperature is above 226 F with A/C Off or 223 F with A/C or Defrost functions requested and vehicle speed is less than 50 mph. When A/C refrigerant pressure is greater than 185 psi, then the cooling fans will run. When certain diagnostic trouble codes are set then cooling fans will operate. The PCM will discontinue primary fan operation when the ignition is turned Off, engine coolant temperature falls below 210 F or A/C pressure drops below 189 psi with A/C selected.
Secondary fan operation begins when engine coolant temperature reaches 235 F with A/C Off or On. The secondary fan will operate if A/C pressure is above 236 psi with A/C requested and vehicle speed is below 50 mph. The secondary fan will discontinue operation if engine coolant temperature drops below 228 F, refrigerant pressure drops to less than 185 psi or the ignition switch is turned to the Off position.
Monday, June 13th, 2011 AT 1:44 PM