Description & Operation: Introduction

The cooling fans are mounted behind the radiator in the engine compartment. The electric cooling fans increase the flow of air across the radiator fins and across the condenser on A/C equipped vehicles. This helps to speed cooling when the vehicle is at idle or moving at low speeds. The main fan size is 11.8" (300 mm) in diameter with five blades to aid the air flow through the radiator and the condenser. An electric motor attached to the radiator support drives the fan. Models equipped with A/C have two fans; the main fan and the auxiliary fan. The auxiliary fan is 11.8" (300 mm) in diameter. Non-A/C equipped models have only the main fan.

With A/C off or non-A/C equipped model, the cooling fans are actuated by the Electronic Control Module (ECM) using a low-speed cooling fan relay and a high-speed cooling fan relay. On A/C equipped vehicles, a series/parallel cooling fan relay is also used. The ECM will turn the cooling fans on at low speed when the coolant temperature reaches 199°F (93°C) and at high speed when the coolant temperature reaches 207°F (97°C). The ECM will change the cooling fans from high speed to low speed at 201°F (94°C) and will turn the cooling fans off at 194°F (90°C).

With A/C ON, the ECM will turn the cooling fans on at low speed when the A/C system is on. The ECM will change to high speed when the coolant temperature reaches 239°F (115°C) or when the high side A/C pressure reaches 270 psi (1859 kPa). The cooling fans will return to low speed when the coolant temperature reaches 234°F (112°C) and the high side A/C pressure reaches 210 psi (1449 kPa).