How to Wire an Automotive Electric Cooling Fan

Electric cooling fans have replaced engine-driven fans since the late 1980s. Electric fans use less power and they can be turned on and off when needed to save both gas and power. Many owners have converted their old engine-driven fans to the new electric cooling fans. Aftermarket kits are available which include the fan, wiring, temperature sensors and instructions for wiring a new electric cooling fan system.

Things You'll Need

  • Wire strippers
  • Wire cutters
  • Plastic twist caps
  • Electrical tape
  • Electric fan
  • Temperature sensor
  • Electrical wire
  • Mount the fan onto the radiator as instructed in the manufacturer's instructions.

  • Connect the negative terminal of the fan to the negative terminal of the battery or to the vehicle chassis. Connect the negative terminal of the temperature sensor to the vehicle chassis and connect the positive terminal of the temperature switch to one of the two coil pins of the fan control relay.

  • Connect the second coil pin to the battery positive terminal. Connect the positive terminal of the fan motor to the center switch position of the fan relay. Fan relays have two pins for the control coil and three pins for the switch. The three pins for the switch can be numbered 1, 2 and 3. If pin 2 is the center pin, then it can connect to pin 1 or pin 3 depending on whether the coil is energized.

  • Connect one of the other switch pins to one end of a 20- to 30-amp fuse. Connect the other end of the fuse to the battery's positive terminal.