Adding a switch to a radiator fan is an economical way of keeping it cool and in good condition. If you're rusty or new to this automotive element, here's a rundown of how radiator fans work. Adding a switch can essentially be a one-two punch, once you know what you're looking for.
Step 1 - Wiring
The first step in adding a switch to a radiator fan is to disconnect the battery's negative terminal. Now find the wire that is connected to the motor of the electric fan. With the help of a wire cutter, cut the wire at a distance of twelve inches from the start point. Attach the electrical connector at both ends of the wire and wind a heat shrink over them.
Step 2 - Connecting the Switch
Take two red AWG wire and strip the ends and slide them on the power wire connectors of the radiator fan. Slide heat shrink over them and use the heat gun over the heat shrinks. Use a power drill to make holes at a location that you think is suitable for the switch. Now manually screw in a toggle switch. Attach the electrical connectors to the switch. Now test the switch by reconnecting the battery. When you turn on the toggle switch it should start engaging the vehicle's radiator fan.