February 10, 2012 By Dave Rongey ©2007-2012Author - Licensed Electrical Contractor Filed under Electrical

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How to Replace a 3 Way Switch with a 3 Way Dimmer Switch

Replacing a 3 Way Switch with a Dimmer Switch

• I just bought a house that has 2 switches that control my living room light.
• I replaced the switch that we use most often with a dimmer switch.
• Now the switch that does not have the dimmer has to be on in order for the dimmer switch to work.
•  Also, when the lights are on they make a buzzing noise that they did not make before with the normal switch. Now, both the old switch and the dimmer switch have 3 posts.
• Looking toward the switch the top right has the black wire, bottom right has white wire, and left side has a red wire (on the dimmer switch).
• I just took the wires off the old switch and put them on the dimmer switch just the way they were. Did I do something wrong?
• The light works and dims but both switches have to be on and now the on position is with the dimmer switch is down… (Its a switch with a sliding dimmer beside it BTW)

Thanks!

This electrical question came from: Robert, a Homeowner from Gloucester, Virginia
See more about Home Wiring for Virginia

Dave’s Reply:
Thanks for your electrical question Robert.

Wiring a 3 Way Dimmer Switch

• This is a relatively easy fix where the wiring at the dimmer switch are out of sequence.
• The wiring may be corrected by identifying the point wire or the pair used for travelers and correcting the connections, which are shown in the 3 way dimmer switch wiring diagrams mentioned below.
• The buzzing that you hear when using the dimmer switch is coming from the filament inside the lamps which is vibrating at the lower control settings of the 3-way dimmer switch.

The Following links will assist you with wiring a 3 Way Dimmer Switch

Wiring a switch

Wiring a Light Switch – Diagram 1

Wiring a dimmer switch

3 Way Dimmer Switch Wiring Diagram
Fully explained 3 way dimmer switch wiring diagram will take the mystery out of wiring a 3-way dimmer switch.

For more information about 3 Way Switch Diagram
3 Way Switch Diagram

3 Way Switch Diagram
In response to the requests for this information, I have developed a comprehensive,step-by-step guide designed to walk you through the identification and wiring of your 3-way switches.