How Do I Configure a Leviton Decora Smart 3-Way Switch?

Problem Description

You want to configure a Leviton Decora Smart switch in a 3-way setup (controlling one light from two switch locations). In a 3-way configuration, one switch location has the line (hot) wire — the smart switch must be installed at that location. The other location uses a matching Leviton remote switch (no smart features needed at that position).

Why This Happens in Real Homes

Configuring a Leviton Decora Smart switch in a 3-way is straightforward once the roles are clear: only one location gets the smart switch, and it must be the location with the line (hot) wire. The other location gets a matching Leviton companion (coordinating remote) that carries no smart features itself — it simply signals the smart switch. You never use two smart switches, and a standard mechanical 3-way won't work as the companion.

Put the smart switch where the line feed lands, connect its neutral, and set line and load correctly. The companion connects to the smart switch over the traveler wire per Leviton's wiring diagram, so getting that traveler on the right terminal is what makes control work from both spots. After the wiring is right, onboard the smart switch in the My Leviton app (or your hub) — the companion needs no separate pairing. Line-side smart switch, matching companion, correct traveler: that's the whole configuration.

Symptoms

• Configuring a Decora Smart 3-way
• Which switch goes where
• Companion won't control the light
• Setup not working from both spots
• Unsure about line vs load location
• Wrong-state after wiring
• Companion model questions
• Pairing the two locations

Recognize these? Here's what usually causes it.

Common Causes

• Smart switch not at the line (hot) location
• Standard 3-way used instead of a Leviton companion
• Traveler not connected to the companion correctly
• Two smart switches used by mistake
• Neutral not connected at the smart switch
• Companion not the matching model
• Line/load reversed
• Firmware/app step skipped

Tools & Requirements

Step-by-Step Solution

1

Identify which switch location has the line (hot) wire

In a 3-way setup with Leviton Decora Smart switches, the smart switch (DD0SR-DLZ or DN6HD) must be installed at the location that has the line (hot) wire from the breaker. Turn off the breaker, remove both existing switches, and use a non-contact voltage tester to find which box has a wire that is hot when the breaker is on. The other box has the load wire going to the light fixture. The smart switch goes in the line box. The companion switch (DD0SR-DLZ or matching dimmer remote) goes in the load box.

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2

Wire the smart switch at the line location

At the line box, connect the black (hot) wire to the brass (hot) terminal on the Leviton smart switch. Connect the white (neutral) wire to the silver (neutral) terminal — Leviton Decora Smart switches require a neutral wire. Connect the bare copper wire to the green (ground) terminal. Connect one of the traveler wires to the traveler terminal (yellow on most Decora models). Leave the second traveler wire capped with a wire nut — the Leviton 3-way system only uses one traveler, unlike traditional 3-way wiring that uses two.

3

Wire the companion switch at the load location

The Leviton DD00R-DLZ matching remote switch goes in the load box. Connect the traveler wire (the same one connected at the smart switch end) to the traveler terminal. Connect neutral to neutral. Connect ground to ground. Connect the load wire (going to the light fixture) to the load terminal. The companion switch does not have a line wire — it communicates with the smart switch over the traveler wire. Do not use a regular dumb switch as the companion — it will not work with Leviton smart switches.

4

Test before closing up the boxes

Turn the breaker back on. Both switches should power up. Test from the smart switch first — the light should turn on and off. Then test from the companion — it should also toggle the light. If the smart switch works but the companion does not, check the traveler wire connection at both ends. If neither switch works, check the neutral wire connections — a loose neutral prevents the smart switch from powering on. The Leviton smart switch indicator LED should glow when powered, even when the light is off.

5

Add to the Leviton Decora Smart app for WiFi control

Once the physical 3-way setup works, add the smart switch to the My Leviton app. Tap the + icon, select your switch model, and follow the WiFi pairing steps. Only the main smart switch (not the companion) connects to WiFi. The companion communicates locally over the traveler wire. After adding to the app, you can control the light remotely, set schedules, and integrate with Alexa or Google Home. The companion switch always works locally even if WiFi is down.

Quick Solutions

Still having issues? This is usually the deeper cause below.

Need More Help? Leviton Support

Note: The contact information below connects you directly to Leviton's official customer support team, not Trunetto. They can help with warranty claims, device replacements, and advanced technical issues.