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How to Wire a Three-Way Electrical 12-volt Switch

by Phil Altshuler

Three-way low-voltage switches are available in several different varieties. There are rocker, toggle and push-pull styles, and they come in a large number of colors and designs. These switches are in automobiles, boats and recreational vehicles. They control accessories that require a two-position switch. Some are available with a light, indicating when the device is on. This is particularly useful when the accessory is not visible from the switch location.

Disconnect the positive battery cable. Locate an appropriate switch-mounting location. Drill or cut an opening to accept the switch.

Mount the switch by removing the outer lock ring on the top of the switch. If you are mounting a rocker switch, you may have to trim the opening with a file to get the switch to fit correctly. Rocker switches snap in without a lock ring.

Use a continuity tester to verify the switch configuration. Route the wires to the switch. You will have one wire connected to a positive 12-volt source, and two wires that go to the loads.

Strip the wires back 3/8 inch. Insert them into the crimp end of the spade connectors. Crimp the ends onto the wires.

Wire the switch by connecting power to the center terminal(s). The loads attach to the other two terminals. Push connectors onto the switch terminals.

Connect the battery and verify that the switch works correctly.


  • If you are going to drill a hole to mount the switch, check behind it before you drill into something. Twelve-volt three-way switches are designed one of four ways. Some have a continuous-on position, located on either side of a center-off position. Others have a momentary-on position, located on each side of the off position. They are available in single-pole double-throw and double-pole double-throw configurations.


  • Always be sure that all power sources are turned off before starting to work on any electrical project.

Items you will need

About the Author

Phil Altshuler has written award-winning ad copy and sales-training literature since 1965. He is an expert in conventional and sub-prime loans, bankruptcy, mortgage loan modifications and credit. Altshuler was a licensed mortgage broker in California and Arizona, as well as a licensed electrical contractor. He has a Bachelor of Science in electronic engineering from California Polytechnic State University.

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  • toggle switch image by Sergey Danilov from