Forte Electric Inc.

Switches and Lights Troubleshooting

There can be many reasons why a light or switch stops working. Some reasons
are more common than others and on rarer occasions it may be a bit more
complicated.
Don't ignore the obvious when faced with a problem

• Be sure the light bulb is working by placing it in a known working fixture
• In Flourescent fixtures change all the bulbs, not just one.
• Be sure the circuit breaker is on and not tripped.

That list may seem silly but I have been on enough service calls to know people
sometimes overlook the obvious.

If all these things check out okay then the next most common problem is a bad
switch. If you pull the switch from the wall and there are 2 wires connected to
the switch and a ground wire you have a single pole switch. Using a voltage
tester you can check from ground to each screw with the switch in the on
position. If you have 3 wires on the switch scroll down the page to 3 way.
If you get power on both screws then your switch is good. If you get no power
reading on one of the screws your switch is bad and needs to be replaced. To
replace the switch first turn the power off supplying that circuit. Next remove the
switch and install the new switch. With a single pole switch the ground will go on
the green screw. The other two wires you removed from the old switch go on
the two brass colored screws on the new switch. Which one goes where does not
matter.

If you see 3 wires on the switch and a ground you have a 3 way switch. In the
case of a 3 way test method is a little different. If you view my 3 way diagrams
You will see there are many wiring combinations possible. When testing the 3
way switch you need to go to the other switch and pull that one out as well. Now
with both switches accessible take a voltage tester and test each of the three
screws one at a time to ground. When you have the switch that has two screws
reading power start with that one. Flip the switch and the screw that had no
power should have power now. Go to the other switch and test each screw to
ground. Take note of which has no power. Now flip the switch and the screw
that had no power should have it now. If at this point you get all these readings
your switches are good. If you get no power on one of these tests then you have
a bad switch.

If you need to replace a three way switch it is imperative that you mark the wires
so you can put them back on the new switch correctly. On a 3 way switch one
wire is the common and the other two are travellers. The common screw is a
different color than the other two screws. The common has to go on the
common on the new switch. The travellers or other two wires can go on either
screw.

If at this point you can find nothing wrong it is probably time to call an electrician.