As you will see most 4 way switch wiring is placed between the wiring of two 3 way switches therefore a 4way switch is installed with two 3way. Toggle the first switch to see if it turns the light on and off.
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4 way switch wired wrong. A 3 way switch and a 4 way switch can sometimes refuse to work. This wiring configuration is no longer allowed as of the 2011 nec if a neutral wire is not present in the switch boxes. If it does it is a good switch. If more than three switches are needed simply place more 4 way switches between the three way switches. Toggle each switch until the light come on. A 4 way switch will only be connected to traveler wires never to a hot source or load wire and never to a neutral wire.
Repeat for the other 3 way switch box. Leave the light on. If i turn the light off with the 4 way switch and attempt to turn it on with any of the other 3 way switches the light will not work. Toggle the next switch to see if it turns the light on and off. Leave the light on. I put the old 4 way switch back and the light worked fine.
From the first 3 way switch through a 3 wire cable the two travelers from the first switch are connected to the travelers on the second switch through the black and the red wires. Follow these steps to find which 3 or 4 way switch is bad. Use a circuit tester to find the bad wire. In the first 3 way switch box connect the pair of wires leading to the 4 way box to the out pair of screws on the switch. Then the black or darkest terminal is connected to a black wire that feeds to the light fixture to get connected on the hot contact on the fixture while the white. Power enters the first light fixture box instead of the first 3 way switch box.
Connect the remaining wire to the in screw. Alternate 4 way switch wiring is fairly complex. Now when wiring the traveler wires between switches make certain that when connecting to the 4 wayswitch that the 2 wires coming from the previous switch connect to a matching pair of screws on the 4 way switch and the other matching pair of screws on the4 way switch connect to the 2 wires leading to the next switch otherwise the switch circuit will not operate properly. If it does it is a good switch. Red wires on top and white on the bottom. Also confirm that each pair of travelers on a 4 way are only connected to one switch per pair.
Order is not important. Connect the other pair of wires which lead to the second 3 way switch to the other pair of screws. I bought another 4 way switch cooper wired it exactly as the old 4 way and had the same problems. 4 way switch wiring 4 way switches provide switching from three or more locations.