GM Service Manual Online
For 1990-2009 cars only

Electric Engine Cooling Fan and Relay

These vehicles use 2 360 mm (14.2 in) cooling fans to aid air flow through the radiator. Electric motors drive the cooling fans. These motors are attached to the radiator. Motor size varies with each engine option.

A coolant temperature switch activates the fan motors. This switch regulates voltage to the cooling fan relay. This switch operates the fan whenever the engine coolant temperature exceeds 110°C (230°F). For location and diagnosis, refer to Electrical Diagnosis. A transducer can also activate the circuit, depending on the A/C compressor head pressure going to the condenser.

The engine cooling fan relays provide the high current required for the cooling fan motors using a low current signal coming from the Powertrain Control Module (PCM). This signal is a function of various inputs.

Refer to Electrical Diagnosis for further information and diagnosis of the cooling fan relay.