Radiator Cooling Fan Motor Relay: Description and Operation

A/C Control, Fan, And Fuel Pump Relays:

The electric cooling fan on this engine is totally controlled by the ECM. The ECM will ground the cooling fan relay, which turns "ON" the fan when the following conditions are met.

^ Coolant temperature sensor signal indicating a temperature greater than 106°C (222°F).

^ A/C head pressure greater than 200 psi (1380 kPa) and vehicle speed less than 70 mph.

^ When the cooling fan is turned "ON" it will stay "ON" for a minimum of 15 seconds.

^ This engine also uses a an override switch which will also turn on the cooling fan if the ECM fails.