Electrical 101

How to Troubleshoot Four-Way Switches

Locate a Bad 4-Way Switch

Usually when a 3-way or 4-way switch fails, lights can be toggled on and off on all but one switch. Any switch that toggles the light(s) on and off is probably working properly. Follow these steps to find which 3 or 4-way switch is bad.

1. Toggle each switch until the light comes on. Toggle the first switch to see if it turns the light on and off. If it does, it is a good switch. Leave the light on.

2. Toggle the next switch to see if it turns the light on and off. If it does, it is a good switch. Leave the light on.

Repeat the process for the rest of the switches.

One of these switches will not turn the light on and off (while the light is on) and that is the bad switch.

Switches are spring loaded to minimize arcing and prolong their life. However, a very small amount of arcing is present when a switch is toggled. A bad switch may not fail completely, burned contacts may cause intermittent failure. Keep this in mind when troubleshooting switches. Intermittent failure could make troubleshooting difficult, especially with 3 and 4-way switches.

How to Test a 4-Way Switch

Turn off power to the switches at the circuit breaker and using a tester, make sure power is off. Pull the switches out from their switch box so you can access the switch terminals. The wire connections do not have to be removed. Find Multimeters

Using a continuity tester or the continuity setting on a multimeter, check continuity between terminals as shown. Actual toggle position can vary with make and model.

The Anatomy of a 4-Way Switch

Since there is no on or off position for a 4-way switch, it can be installed with the black terminals on the top and the brass terminals on the bottom or vice versa.

When the toggle is in one position, the left side black terminal connects to the left side brass terminal. The right side black terminal connects to the right side brass terminal.

When the toggle is in the other position, the left side black terminal connects to the right side brass terminal. The right side black terminal connects to the left side brass terminal.

Actual toggle position can vary with make and model