4-way switch configurations are used to control lights with three or more switches. A 3-way switch is used on each end with one or more 4-way switches in between the two 3-way switches. They do not have an on/off position like single pole switches. It is important to understand how these switches are wired before attempting to troubleshoot or replace. Below is a conventional wiring diagram for a 4-way switch configuration.
The diagrams below show the conventional wiring for 3-way switches in a 4-way configuration. Unfortunately, not all 3-way switches are wired the conventional way. See Alternate 3-Way Switch Wiring Configuration for another way 3-way switches may be wired.
If you have any problems with these switches, it may be best to call an electrician.
Conventional 4-Way Switch Wiring
4-way switches have four terminals each with two pairs of travelers (one set usually black and one set usually brass color). A four switch configuration will have two 3-way switches, one on each end and two 4-way switches in the middle.
In the diagrams below, the first switch (3-way) common terminal connects to line voltage.
The first switch (3-way) travelers (brass color) connect to one pair of the second switch (4-way) travelers (black or brass color).
The other pair of the second switch (4-way) travelers connect to one pair of the third switch (4-way) travelers.
The other pair of the third switch (4-way) travelers connect to one pair of the fourth switch (3-way) travelers.
The fourth switch (3-way) common terminal connects to the load (lights).