Installing a 3-Way Dimmer Switch

A dimmer.
  • 1 hours
  • Beginner
  • 35
What You'll Need
Dimmer Switch
Voltage Tester
Black electrical tape

Installing a three-way dimmer switch on an existing three-way switch circuit is not only a simple job, but it will add flexibility to your lighting design and improve the overall atmosphere of your living space. The primary thing that confuses most do-it-yourselfers is the fact that only one of the three-way switches needs to be replaced with the dimmer switch. If you replace both current three-way switches with two three-way dimmers, the circuit won’t function properly.

Your first step is to think about which of the two switches you use the most. This is the one that you should replace with the dimmer.

Follow these steps to replace an existing three-way switch with a three-way dimmer switch.

Step 1 - Turn Off Power

Turn off the power to the circuit.

Step 2 - Take Off the Cover

Remove the cover plate from the switch.

Step 3 - Unscrew

Remove the two screws that secure the switch to the wall box and gently pull the switch out. Double-check with a voltage tester that the power is off.

Step 4 - Position the Switch

Position the switch so that the side with the two screws is facing your right.

Step 5 - Hold Up the Dimmer

Hold up the three-way dimmer next to the existing three-way switch in the same manner.

Step 6 - Remove Wires

Remove the red wire from the existing three-way switch and connect it to the same place on the dimmer switch. In most wiring applications, the red wire is connected to the single screw on the left side of the switch.

Step 7 - Connect Wires

Take the wire that is connected to the dark screw on the right side of the existing switch and connect it to the dark screw on the new dimmer switch.

Step 8 - Connect to Screws

Remove the last wire on the switch and connect it to the bottom screw on the right-hand side of the dimmer.

Step 9 - Connect the Ground Screw

Connect the ground wire to the ground screw on the dimmer switch.

Step 10 - Use Electrical Tape

Wrap the dimmer’s terminals with electrical tape and install it into the wall box.

Step 11 - Add Cover Plate

Install the new cover plate and turn the circuit back on.

That’s all it takes to replace an existing three-way light switch with a more innovative three-way dimmer switch.