Chart C-12, Engine Cooling Fan 2.8L TPI: Notes

The cooling fan is totally controlled by the ECM based on inputs from the coolant sensor and fan control switch. The fan should run if coolant temperature is more than 226°F (108°C). Battery voltage is supplied to the fan relay on terminal "E", and ignition voltage to terminal "C".

Grounding circuit No. 335 (relay terminal "B") will energize the relay, and supply battery voltage to the fan motor. Once the fan relay is energized by the ECM, it will remain on for a minimum of 30 seconds.

The fan control switch mounted, in the A/C high pressure line, will open when head pressure exceeds 200 psi (14 kg/cm² ). This input causes the ECM to ground circuit No. 335. If a code 14 or 15 sets or the ECM is operating in the fuel back-up mode the ECM will turn on the cooling fan.

NOTE: Test numbers refer to test numbers on diagnostic charts.

With diagnostic terminal grounded, cooling fan control driver will close, which should energize fan control relay.
If A/C fan control switch or circuit is open, the fan would run whenever A/C is requested.
With A/C clutch engaged, A/C fan control switch should open, when A/C pressure exceeds 200 psi (14 kg/cm² ).