Which fan speed terminal does this diagram use on the Taurus fan?

The diagram wires the relay output (red wire) to the fan's HIGH terminal; the LOW terminal is shown unconnected, and GROUND goes to chassis ground.

What relay and temp sensor are specified in this diagram?

The relay is labeled RELAY ST85, and the temperature sensor is labeled TEMP SENSOR 233203, using terminals 2 and C.

How is the fan relay triggered in this circuit?

Ignition power from the KEY (IGN) passes through an ON/OFF switch (yellow wire) to terminal 2 of the temp sensor; terminal C of the sensor connects via a dark blue wire to the relay coil, with the relay also grounded.

Where does the fan get its main power?

Main power runs from the battery (BATT) via a red wire to the ST85 relay, and the relay's switched output feeds the Taurus fan's HIGH terminal.

Does the diagram include a manual override for the fan?

Yes, an ON/OFF switch is placed in the ignition-fed trigger wire between the KEY (IGN) and the temp sensor, allowing the trigger circuit to be switched off or on.

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Taurus Electric Fan Wiring Diagram - Relay, Temp Sensor 233203 (Ford Bronco Swap)

Wiring diagram for a Taurus electric fan with relay, temp sensor, and switch

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Wiring diagram for a Taurus electric cooling fan showing battery, ST85 relay, temperature sensor, key switch, and high/low fan speeds.

AI caption October 2005 · Photo 84 of 152

This is a hand-drawn electric cooling fan wiring diagram, uploaded to the gallery of a 1979 Ford Bronco, showing how to wire a Ford Taurus electric radiator fan into a vehicle using a Bosch-style relay (labeled RELAY ST85) and a temperature sensor/switch (part number 233203). Power flows from the battery (BATT) via a red wire to the relay, and from the relay's switched output to the fan's HIGH speed terminal. The relay coil is triggered by a circuit that runs from the ignition (KEY, IGN terminal, with CON also labeled) through an ON/OFF toggle switch (yellow wire) to terminal 2 of the temp sensor; terminal C of the temp sensor connects via a dark blue wire to the relay. Grounds (black wires) are shown for the battery, relay, and the fan's GROUND terminal. The fan's LOW speed terminal is left unconnected. A reader can learn the basic circuit layout for a thermostatically controlled Taurus fan conversion: ignition-switched trigger with manual override switch, temperature sensor controlling the relay, and relay switching battery power to the fan's high-speed circuit. The document contains no year, make, or model statement of its own.

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Frequently asked questions

Which fan speed terminal does this diagram use on the Taurus fan?: The diagram wires the relay output (red wire) to the fan's HIGH terminal; the LOW terminal is shown unconnected, and GROUND goes to chassis ground.
What relay and temp sensor are specified in this diagram?: The relay is labeled RELAY ST85, and the temperature sensor is labeled TEMP SENSOR 233203, using terminals 2 and C.
How is the fan relay triggered in this circuit?: Ignition power from the KEY (IGN) passes through an ON/OFF switch (yellow wire) to terminal 2 of the temp sensor; terminal C of the sensor connects via a dark blue wire to the relay coil, with the relay also grounded.
Where does the fan get its main power?: Main power runs from the battery (BATT) via a red wire to the ST85 relay, and the relay's switched output feeds the Taurus fan's HIGH terminal.
Does the diagram include a manual override for the fan?: Yes, an ON/OFF switch is placed in the ignition-fed trigger wire between the KEY (IGN) and the temp sensor, allowing the trigger circuit to be switched off or on.