How to Troubleshoot And Repair Your Home-s Three-way Switches, Part 1

Three-way switches connect to other switches in the home.

While some lights and other devices in the home are controlled by one switch, some lights can be controlled by two switches. Three-way switches connect to each other and one fixture, allowing you to turn on a light or device at the bottom of the stairs, for instance, and turn it off at the top. Wiring issues with the switch may cause the unit to preform improperly, requiring troubleshooting.

Difficulty:

Moderately Easy

Instructions

Things You'll Need

• Circuit tester
• Screwdriver

1. Turn off the electricity to the room you are working in at the circuit breaker.

2. Remove the screw from the faceplate for the switch. Pull the switch out from the wall.

3. Find a set of white (neutral) wires joined with a wire nut. Remove the wire nut from the white wires but keep them connected. Ensure there aren't any black wires touching the white wires.

4. Turn on the electricity for the room to test the wires. Be careful not to touch any exposed wires.

5. Touch one probe of a circuit tester to the exposed white wires and one probe to each of the black wires, one at a time. The wire that makes the circuit tester glow is the hot wire. Turn off the circuit breaker and mark this wire with masking tape.

6. Locate the wire that goes to the light fixture. Wire nut the hot wire marked with the tape to the wire going to the light fixture.

7. Repeat with the second three-way switch in your room. This ensures all the wires work correctly.

References

• Fort Electric: Troubleshooting 3 Way and 4 Way Switches with Wiring Diagrams
• The Circuit Detective: 3 way Switch Troubleshooting 3 way Switch Diagrams
• Ask the Builder; Fixing Three-Way Switch and Four-Way Switch Wiring Problems; Tim Carter