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Why Light Switches May Not Be Working

Why did my light switch stop working? The Most Common Problems with Light Switches and How to Fix Them. Wiring More Than One Light Switch in the Same Switch Box.

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Guide to Wiring Multiple Light Switches
[ad#block] Electrical Problem: Why did my light switch stop working?
I have a 3 way light switch that is not working.

This electrical question came from: Mike, a Homeowner from Meridian, Idaho.
See more about Home Wiring for Idaho

Additional Comments: Great site.

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


How to Fix Wiring Problems with Light Switches

Application: Wiring Light Switches.
Skill Level: Intermediate to Advanced, Best installed by a licensed electrical contractor.
Tools Required: Basic Electricians Pouch Hand Tools and a Voltage Tester.
Estimated Time: Depends on personal level experience, ability to work with tools and the access to the switch box for wiring for the switches.
Precaution: Identify the circuit, turned it OFF and Tag It with a Note before working with the light switch wiring.
Notice: Modifying existing wiring or installing additional electrical wiring should be done according to local and national electrical codes with a permit and be inspected.

The Most Common Problems with Wiring Light Switches and How to Fix Them

When wiring more than one light switch in the same switch box the power source(s) will need to be identified and the circuit wiring must be understood in order to make the correct wiring connections for all of the light switches within the same switch box. The following guide will help you identify the circuit wiring.

Wiring More Than One Light Switch in the Same Switch Box

More about Wiring Light Switches and Circuit Wiring Diagrams

Using Electrical Testers

When working on home electrical wiring using voltage testers can play an important part in electrical safety. Electrical testers enable you to identify electrical circuits and help prevent the possibility of accidental electrical shock.
Types of Electrical Testers

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Basic Home Electrical Wiring by Example

Dave's Guide to Home Electrical Wiring:

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Complete Guide to Home Electrical Wiring

Perfect for Homeowners, Students,
Handyman, Handy Women, and Electricians
Wiring GFCI Outlets
Wiring Home Electric Circuits
120 Volt and 240 Volt Outlet Circuits
Wiring Light Switches
Wiring 3-Wire and 4-Wire Electric Range
Wiring 3-Wire and 4-Wire Dryer Cord and Dryer Outlet
How to Troubleshoot and Repair Electrical Wiring
Wiring Methods for Upgrading Electrical Wiring
NEC Codes for Home Electrical Wiring
....and much more.

Be Careful and Be Safe - Never Work on Energized Circuits!
Consult your Local Building Department about Permits and Inspections for all Electric Wiring Projects.

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FAQs Frequently Asked Questions and Comments

2 Responses to “Why Light Switches May Not Be Working”
  1. joe thompson says:

    I’m installing a new light switch. There were two black wires and one green wire connected to the old switch. I connected the ground wire to the new switch and the two black wires to the side connecters but the light will not come on.

  2. Dave Rongey says:

    Hi Joe,
    Here are some possibilities why a light fixture is not working after a replacement switch has been installed:
    No circuit power to the switch – Make sure the circuit is on.
    A faulty light switch – The switch should be tested..
    The wrong replacement switch has been installed – Make sure the replacement switch is correct.
    The switch is not wired correctly – Be sure the wiring configuration is as it was before replacing the switch.
    The light bulb(s) are bad and need to be replaced.
    I hope this helps.