What Is Continuity?
Special testing devices like a continuity tester or multimeter can be used to check continuity.
Also, ensure the circuit has power and hasn’ttripped its circuit breakeror blown afuse.
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It’s also possible that wire connections going to the switch are loose and not making proper contact.
This problem is often corrected simply by shutting off the circuit and retightening the wire connections.
Switches have a limited lifespan, and the springs and other inner components can eventually wear out.
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To ensure you’re not performing an unnecessary replacement, test the switch for continuity.
You must ensure the circuit has been shut off before you handle the switch or its wire connections.
Home wiring systems can take many forms depending on when (and if) the wiring was last updated.
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Need more help?
The multimeter also has options to test for power.
verify you test the testing devices.
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This makes it much easier to use a multimeter as a continuity tester.
Amultimetercan also be used to detect voltage in circuit wiresprovided you know how to use it.
Note the number of side terminals on the switch.
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If there are two side terminals, it is asingle-poleswitch.
If the switch has three terminals (plus a ground screw), it is athree-way switch.
This is the “common” terminal that brings power to the switch.
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Four-way switches have four screw terminals, in addition to the green grounding screw.
Four-way switches are not common and your home may not have any at all.
Bring the switch to your work surface for testing.
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A very small screwdriver or nail usually works to release the wire.
Turn the switch lever on and off.
Touch each tester probe to one of the screw terminals, then turn the switch lever on and off.
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Flip the switch lever to both positions.
The tester should light up when the switch is in one position but not in the other position.
If the switch does not behave in this way, it indicates the switch is bad.
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Turn the switch lever from one position to the other.
The tester should read close to 0 in one position and 1 in the other position.
It should show continuity when the lever is in the opposite position from the first test.
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Testing with a multimeter is a similar process.
The switch should show continuity with the lever in one position but not both.
If the switch fails any continuity test, it is faulty and must be replaced.
Tighten each screw terminal and the ground screw securely.
An old switch may not have a green grounding screw, while new switches always have this screw.
Reinstall the cover plate.
Turn the power back on to the circuit by switching on the circuit breaker or reinstalling the fuse.
Test the switch for proper operation.
A switch can’t usually cause a fire, but faulty wires within the switch can arc and spark.
