My house has an outside light over the garage door which doesn't work.
My goal is to replace it with an automatic flood light. There is a
light switch plate inside the garage on the same wall that has two
switches, one for the lights inside the garage and one presumably for
the outside one.
I have taken the light fixture off and checked the wires but don't see
any voltage there no matter what position the switch is in. My next
step is to take the switch plate apart and check for voltage there.
Would I be right to assume both switches should be on the same circuit?
What other troubleshooting tips do you have?
I think it worked at one time. Can't remember for sure.
One inside switch is a three-way switch for my inside garage lights and
it's seldom used because it's on the garage door side. The other one
on the wall plate is for the outside light above the garage door that
isn't working now.
On Monday, January 11, 2016 at 10:49:56 AM UTC-5, badgolferman wrote:
That's what I would do.
But I would check something that I know has power - an outlet that works, f
or example - to be sure the meter you are using reads correctly. I'm assum
ing you are using some kind of multimeter, probably one of the inexpensive
digital ones. That should work fine for your purpose, but make sure that i
t works and is set correctly (you want AC voltage, not one of the other cho
I would check from hot to neutral and hot to ground, even if I had to use a
jumper cable to reach a ground.
It, presumably, is for *an* outside light. Are you sure that
there aren't any other switches that also might control that
light? (e.g., is it a "three-way" switch, perhaps miswired or
with one of its "associates" in a "middle" position)
The switch can also be broken. I've seen a fair number of the "Decora"
style switches break (flimsy plastic) over the years.
Probably, but that's not guaranteed. Are all of the breakers 'on'
(none tripped or 'off')?
With anything electrical, it goes without saying that you should
be thinking long and hard about whether or not you feel qualified
to do this "to save a few bucks". It only takes an ohnosecond to
stop a heart...
You can start by removing the switch plate and *looking* to see
what is visible (hands in pockets). The sides of the switches
should be visible so you can see if there are loose connections
(unless they've been wrapped in tape).
You can carefully remove each switch -- taking care not to
nudge the adjacent switch or its yolk (which could draw an arc).
From there, *count* the number of wires entering the Jbox
and make a drawing of any wirenuts/connections so you can
determine if the box is fed power.
Note that you may *not* have a neutral present in the box
against which to measure the available potential on the "hot".
Hopefully, you'll have a "ground" to act as a reference.
If the jamoke who preceded you was another DIY'er, there's
no telling what you'll find. So, you can't even assume that
what you see is wired correctly.
[Hence the suggestion to look for "qualified help"]
If the guy doesn't know how to check the circuit and wants to play
with it anyway, the FIRST thing he needs to do is shut off power to
the circuit - at the breaker - and then CONFIRM it is off. After
confirming power is off, remove the switch - (assuming it is still
live) then double-ensure the power is off. Then check for bad
connections, and check the switch with ohm-meter.
If he doesn't know how to do this - CALL AN ELECTRICIAN.
Better that than the MORTICIAN.
On 1/11/2016 1:14 PM, firstname.lastname@example.org wrote:
That's not practical.
He (admittedly) doesn't know which circuit is involved. He
can't verify power is removed -- unless he can gain access to
the switch contacts (so, he has to be able to extract the
switches from the Jbox to make those contacts accessible -- BEFORE
he KNOWS power is "off"!)
Also, as he has no signs of power REGARDLESS OF THE POSITION OF
THE SWITCH, he has no way of confirming that he has *cut* power
to that circuit -- unless he trips the main for the entire house.
Hence the advice "(hands in pockets)".
You can do a lot of troubleshooting with just your eyes -- given
that the circuit appears "dead" (at the load).
Removing a switch from a box is also relatively low risk -- as
long as you hold onto the yoke and don't fall for the temptation
to grab the body of the switch between your fingers. If you pull
it straight out, it will also tend to easily go straight *back*
in (the wire dressing acting like an accordion).
No need to "ohm" the switch. Look for line voltage on either side
of it. If present on one side and not the other, switch is bad
(after exercising the switch into both positions).
If present on neither side, problem lies elsewhere.
On Mon, 11 Jan 2016 15:49:49 +0000 (UTC), "badgolferman"
Probably, but why think about things like this? You'll find out when
you find out and the procedure is the same either way. Check for
voltage wrt ground at both sides of the non-useful switch. When you
find that one screw is hot, check for voltage on the other side when
the switch is in the ON position. If one side has 120 and the other
side has little or nothing, the switch is bad.
If neither side of that switch has voltage but the other switch does,
as it must if it's controlling a light, well, that's not likely to be
If the switch is a "drop" switch and the bulb is dead or a wire is
off at the light, or something else is wrong in the fixture, there
WILL be no power at the switch. - but there would be power at the
On Mon, 11 Jan 2016 15:49:49 +0000 (UTC), "badgolferman"
The house I lived in in JHS and HS had a switch that did nothing. It
was intended for light at the foot of the driveway, that no one had
installed yet. I wanted to put it in, but the wires were either in
the always wet, always muddy crawlspace (20 feet or more from the
trapdoor entrance) or under the floor in the attic.
Plus I don't think my mother would have let me dig up the lawn. We
really didn't need a light. I just wanted one because others had it.
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