Dimmer switch wiring

QuestionEdit

QUESTION: I would like to replace the ¡°outside light¡± switch with a dimmer. This are shown on the attached diagram. There are 2 switches in the box that seem to be a 3-way or double pole (it says ON/OFF) and a 4-way. The 4-way is connected directly through the common to the other switch. When I wire the 3-way dimmer (2 red, 1 black and ground), I get power to the ¡°outside lights¡± but nothing to the ¡°inside lights¡±. I can¡¯t figure this out and am asking for help. Thanks, Rick

ANSWER: If the switch says on and off, it is a single pole switch. Is there more than one switch controlling any of the lights that these switches control? If there are only 2 screws on a switch, not counting the green one, it is a single pole switch. A 3 way switch is used if 2 or more switches control one light. A 4 way switch is used if 3 or more switches are used to control one light.

There should be one black wire that brings power to both switches. This wire needs to go to one terminal on each switch. If you are using the push in tabs in the back, they can fail. Best to use the screws. Use wire nuts and pigtails if you need to connect more than one wire on a screw.

If these are both single pole switches, in addition to the black power wire going to each switch, there should be one other black wire going to the remaining screw of each switch.

I hope this helps. Feel free to ask a follow up question if you can give me more details on the switches.

---------- FOLLOW-UP ----------

QUESTION: Thanks for the quick response. Although the left switch says ON/OFF it is also controlled by another switch so must be a 3-way. Perhaps it is incorrectly wired. The switch on the right is also controlled by 2 other switches. Thanks again.

AnswerEdit

A three way switch needs to have 3 screws, not counting the green ground screw. The two that are the same color are connected to the same two screws on the other switch. The remaining screw on one switch goes to the light hot wire, the remaining screw on the other switch goes to the hot power source.

A four way switch has a 3 way switch on either side of it. If you cut the 2 wires going between the 2 switches, you have 4 ends, each of which goes to the 4 terminals of a 4 way switch.

Do you have all the screws and wires that are required? If not, it would be impossible to tell you how to wire it up.