I have a light switch on my bedroom closet that exhibits erratic behavior: about half the time when the switch is flipped from off to on, the light remains off. Flipping the switch back off and on eventually gets the light to turn on.
switch: off -> on -> off -> on -> off -> on
light: .off..................on...off.....on
How can I diagnose what's going on here?
It's probably just a broken switch. My guess would be that the switch contact is worn out to the point that it does not make contact, but jiggling it a bit (by turning off and on again) may solve the problem, at least for a little while.
Replacing a light switch is a pretty simple matter for a DIYer. I recommend swapping it out and seeing if that solves the problem.
An intermittent problem like that is almost always a broken switch or a loose connection. Often, you can "feel" when a switch is broken, so if it feels normal to you, then a loose connection might be the issue. Either way, you need to pull the switch out and check it out. If you are lucky and it is a loose wire, you'll just need to tighten the screw holding the wire and you're done.
It's possible that whoever installed the switch didn't use the screw connectors and pushed the wires into the holes on the back instead. Ugh. If that is the case, just cut the wires at the back of the switch and try the screw connectors instead.
Switches are cheap, so don't spend a lot of time trying to fix this. If the problem isn't obvious, replace the switch.
