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Bathroom light won't work

7464 Views 7 Replies 4 Participants Last post by  dmxtothemax
My old bathroom light started to flicker from time to time. No other lights on that circuit or anywhere else in the house were affected. One day, the bathroom light stopped working altogether. I decided to go with a new light. I installed it and it doesn't work. The way the light is wired is: switch->light->GFCI receptacle. The really weird thing is that when there are no lightbulbs in the fixture, the green light on my GFCI is "on". As soon as I put a bulb in the light fixture, the green light on the GFCI goes off. The GFCI is not tripped, just no power. At no point does the light actually work. I don't want to do anything crazy but I am at a complete loss as to what the problem is and would appreciate any suggestions your members may have. Thank you.
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What type light?
Trying to use a dimmer?
Checked for loose connections?
Sounds like a loose conection somewhere !
This would explain the flickering,
Start at the beginning
1- test for power at recepticule.
2 - test for power at switch loop.(behind fitting).
3 - test for power at switch.
4 - test for power at lamp base.

Use a non contact type tester at these four spots
and report your findings ?
I will check for loose connections again. The only thing I didn't look at so far is the GFCI. Could that be the problem? The weird thing is I lose power at the outlet when I screw a lightbulb into the light fixture. When there is no lightbulb in the fixture, there is power at the outlet. Anyway, I will check for power and any loose connections and then report back to you. Thank you both.
Ok. I checked for loose connections: none
Power at switch: check
Power at light fixture: check
Power at GFCI: check

All of the above occurred with NO light bulbs in fixture. As soon as I screw in a single light bulb, no power at fixture or GFCI, but still have power at switch. I even disconnected the GFCI to see if it made a difference. It did not. I am at a loss.
Ok. I checked for loose connections: none
Power at switch: check
Power at light fixture: check
Power at GFCI: check

All of the above occurred with NO light bulbs in fixture. As soon as I screw in a single light bulb, no power at fixture or GFCI, but still have power at switch. I even disconnected the GFCI to see if it made a difference. It did not. I am at a loss.
Sounds like the switch leg is messed up in the switch box and it feeds through the GFCI.
Sounds like the switch leg is messed up in the switch box and it feeds through the GFCI.
Not sure what that means, but I replaced the switch with a new one so now I have new switch, new light and bulbs, and still no light. It goes: switch>light>GFCI. Outlet works with no light bulbs in the fixture but doesn't work with light bulbs in the fixture. Power is at the fixture with no light bulbs in it but no power when I put in bulbs. As soon as I start screwing the first bulb in, the GFCI goes dead, but not tripped. No blown fuses either. I'm trying to figure out how putting a bulb in can kill a circuit. I wonder if I mixed up a wire in the junction box but I'm going white-white and black-black. Pretty sure it was that way before.
Most likely you have a high resistance joint somewhere !
With no load the voltage drop across the bad joint is very low !
But when you put a real load on the line then the voltage drop
across the bad join is signifcant ! (so no light).
Dont forget the bad join could also be in the neutral side !

1 - start with a test lamp



(sorry about the old pic, all I could find at short notice)
Attach it to gfci load side and neutral.
does it light fully ?

If so move on to where power joins to switch loop
at the light fitting, test here.

if ok, check other side of switch loop (return side)
does it light fully ?

be carefull and safe about it !

Post results !
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