What components are needed for this e-fan control circuit?

Per the diagram: a battery, a fan relay, a diode, a temp sensor, an ON/OFF/ON switch, and the electric fan itself.

How is the electric fan turned on automatically?

The fan relay is triggered by a temp sensor, which is wired through one ON position of the ON/OFF/ON switch.

What does the ON/OFF/ON switch do?

It selects between manual fan operation (one ON position), automatic operation via the temp sensor (the other ON position), and OFF.

Why is there a diode in the circuit?

The diagram shows a diode wired between the fan/relay output and ground; it is labeled simply 'DIODE' with no further explanation given in the document.

Who created this wiring diagram?

Home/ Registry/ Jeep/ Wrangler/ 1997-2006/ “Ruby”/ Photo supermotors.net/registry/media/297894

Electric Fan (E-Fan) Relay Wiring Diagram - Temp Sensor & Manual Switch Control

Electric fan control wiring diagram with fan relay, temperature sensor, and on/off/on switch

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Electric cooling fan control wiring diagram showing the fan relay, temperature sensor, and an on/off/on switch from the battery.

AI caption March 2006 · Photo 187 of 364

This document is a simple schematic wiring diagram titled 'E-FAN CONTROL' showing how to wire an electric cooling fan (e-fan) circuit. The diagram depicts an electric radiator fan on the left, connected to ground and to a fan relay. The fan relay's coil and switched contacts are fed from the battery, which is shown grounded. A diode is wired across the fan circuit to ground (for spike suppression). Control of the relay is provided through two paths: a temperature sensor (temp sensor) and a three-position toggle switch labeled ON / OFF / ON, allowing either automatic operation via the temp sensor or manual override via the switch. The diagram is drawn in a simplified block style with no wire colors, gauge specifications, fuse ratings, or part numbers indicated. The image is credited 'Copyright 2004 RJM Injection Technologies' with the website www.fordfuelinjection.com. Although uploaded to a 1998 Jeep TJ gallery, the diagram is generic and does not state any specific vehicle year, make, or model applicability; it can serve as a general guide for adding a relay-controlled electric fan with manual/automatic switching to virtually any 12V automotive electrical system.

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Frequently asked questions

What components are needed for this e-fan control circuit?: Per the diagram: a battery, a fan relay, a diode, a temp sensor, an ON/OFF/ON switch, and the electric fan itself.
How is the electric fan turned on automatically?: The fan relay is triggered by a temp sensor, which is wired through one ON position of the ON/OFF/ON switch.
What does the ON/OFF/ON switch do?: It selects between manual fan operation (one ON position), automatic operation via the temp sensor (the other ON position), and OFF.
Why is there a diode in the circuit?: The diagram shows a diode wired between the fan/relay output and ground; it is labeled simply 'DIODE' with no further explanation given in the document.
Who created this wiring diagram?: It is marked 'Copyright 2004 RJM Injection Technologies, www.fordfuelinjection.com'.