Chevrolet Equinox Service Manual: Cooling Fan Description and Operation (LFX) Engine Cooling Radiator Fan

System Overview

The engine cooling fan system consists of2-electric cooling fans and 3-fan relays. Thecooling fan relays are arranged in a series/parallel (S/P)configuration. This allows the engine control module (ECM) tooperate both fans together at low or high speeds using2-fan control circuits. The cooling fans receivepositive voltage from the cooling fan relays, which receive batterypositive voltage from the underhood fuse block. The cooling fansare supplied a ground at G101.

Low Speed Operation

The ECM applies ground to the coil side of the cooling fanlow speed relay. This energizes the coil and applies voltagedirectly to the left cooling fan through the switch side of the lowspeed relay. The left cooling fan is connected in series to theright cooling fan through the de-energized series/parallel (S/P)cooling fan speed control relay. The result is a series circuitthat operates both fans at low speed.

High Speed Operation

The ECM applies a ground to the coil side of the cooling fanlow speed relay, the S/P cooling fan speed control relay, and thecooling fan high speed relay. When energized, the high speed fanrelay applies voltage directly to the right cooling fan through theswitch side of the relay. Simultaneously, the low speed fan relayand the S/P speed control relay provide ignition voltage and adirect path to ground for the left cooling fan. During high speedfan operation, both engine cooling fans have their own ground path.The result is a parallel circuit with both fans operating at highspeed.