INSTALLING LIGHT SWITCHES You might have to install a new light switch with your new fixture. This is not a difficult task. The three most common types of light switches used in homes are single-pole, three-way, and dimmer switches. When only one switch ... switch with. Fig. 8-2. Wiring diagram for a single-pole light switch. Fig. 8-3. Replacing a light switch with a dimmer switch. 38 Home Improvements.