Troubleshoot a three-way switch by turning off the circuit breaker and using a continuity tester to check between the common terminal and each of the traveler terminals. If the switch is working correctly there is only continuity between the common terminal and one of the travelers. Toggle the switch to test the other traveler terminal if the first passes the check. If there is no continuity between terminals, replace the switch.Continue Reading
Three-way switches allow controlling the power to a light fixture from two different places in a room. When combined with four-way switches, it is possible to install three or more switches to control a single fixture. If the three-way circuit is not working correctly, the switch is the most common issue.
The common terminal of a three-way switch connects to the terminal in the breaker box. Each switch also connects to two traveler wires. The terminal to which the travelers connect to the fixture only supplies power when both switches are in the correct position. Flipping one of these switches disconnects the power from the light. A second flip of either switch reconnects the power, illuminating the light. If the system does not work correctly after replacing one of the switches, the other may also be bad, so try replacing it.Learn more about Electrical