Ask This Old House master electrician Scott Caron looks at a three-way switch issue and fixes the problem.
1. Scott first gives an explanation of the three-way switch- two switches that control one light fixture.
2. There are many ways that a three-way switch can be wired, but usually power or the light fixture connect to the load side of the switch and traveler wires run between traveler screws on both switches.
3. In this case, the traveler wire and load wire were swapped and repairing the circuit involved switching them back.