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Test a 4-way Switch

  1. Turn off power to the switches at the circuit breaker and using a tester, make sure power is off. Remove all of the switches so you can access the switch terminals. The wire connections do not have to be removed.
  2. Follow the How to Troubleshoot 3-way Switches link to test the 3-way switches.
  3. Using a continuity tester on the 4-way switches, check continuity between one of the black terminals and each of the brass colored terminals. There should be continuity between the first black terminal and only one of the brass terminals.
  4. After toggling the switch, check continuity between the other black terminal and each of the brass colored terminals. There should be continuity only between the second black terminal and the brass terminal that did not show continuity in step 3.

When a 4-way switch fails, there will usually be no continuity In step 3 and/or step 4.

Step 3

Step 4

4-way Switch Up Position 4-way Switch Up Position

Place leads of continuity tester on the second black terminal and one of the brass terminals

Place leads of continuity tester on the second black terminal and the other brass terminal

Place leads of continuity tester on one of the black terminals and one of the brass terminals

Place leads of continuity tester on the same black terminal and the other brass terminal

How to Troubleshoot Four-Way Switches

4-way Switch Down Position4-way Switch Down Position

Question or Comment?

Switches are spring loaded to minimize arching 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.

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 come 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.