Radiator and Condenser Fan Controls
Fan control system:
The cooling fan system is comprised of the radiator fan, condenser fan (left and right), engine compartment fan, radiator
fan low relay, radiator fan high relay, condenser fan relay, engine compartment fan relay, radiator fan resistor, radiator
fan control sensor, A/C pressure switch, fan control unit, climate control unit, and ECM.
The fan control unit controls the operation of the radiator fan and condenser fans.
It uses inputs from the radiator fan control sensor and the A/C pressure switches (A and B) in the A/C system to deter-
mine when the fans should run and at what speed.
Additionally, the temperature switch shuts down the A/C system if the engine coolant temperature (ECT) exceeds
266°F (130°C). If the pressure in the A/C system is higher than normal, pressure switch A closes and the fans will run at
high speed only. See the A/C section for the description and specifications of that function.