Chart C-12, Engine Cooling Fan (With A/C): Notes

The engine cooling fan will run on low speed when A/C compressor clutch is engaged. Battery voltage is applied to terminal No. 86 of low-speed fan relay through A/C compressor clutch relay. This closes relay and completes circuit as follows: through fuse No. 14, circuit No. 340, relay switch, circuit No. 340 and .6-ohm resistor, to fan motor.

The high-speed cooling fan relay is controlled by ECM. The ECM will ground circuit No. 939, actuating relay. Once this occurs, the high-speed fan motor circuit is completed as follows: through fuse No. 14, circuit No. 440, relay, and circuit No. 903, to fan motor. The ECM will run the cooling fan at high speed if the any of following conditions exists:

• Trouble Codes 14 or 15 are present.
• Engine coolant temperature is greater than 225°F (107°C).
• Engine coolant temperature is between 79-225°F (26-107°C) Vehicle speed is less than 44 MPH, and high-pressure blower switch is closed.