Electrical Question

[DavidMcmillan]

One fixture with three bulbs. It will work with two LEDs and one incandescent, in any combination. No matter which two sockets I use for LED, the third one will only work with incandescent. I have never encountered anything like it. I may have to replace the fixture. Crazy!

Thanks for all the suggestions. I’ll post when this mystery is solved.

 

[swampratt]

You are trying the same 3 bulbs correct?

Pull all 3 bulbs from the other bathroom that work in that other 3 light fixture and try them.

I am going with one of the wires on the fixture has been reversed.
Some LED bulbs are polarity sensitive as was stated.

 

[rickm]

Not saying this is your problem but i have run across some sockets that wont let the bulb screw in far enough and then i have also come across some bulbs that the screw in part is to short also so if you get one or the other or a combination of both the bulb wont work.

 

[KOPBET]

Are the working and non-working fixtures on the same circuit breaker?

If not, check the breaker for the non-working fixture, connection at the breaker, and it's associated neutral wire connection at the bus bar for loose or corroded connections. As mentioned, check the connections at the fixture as well and the switch leg at the switch. Make sure the switch leg is actually the hot side.

 

[SoonerP226]

Some LED bulbs are polarity sensitive as was stated.

If it were a polarity issue, it should always happen in the same socket, but, if I read it correctly, the LED bulbs will work in all three sockets, just not if all three sockets have LED bulbs in them. To me, that points to a voltage issue, where there's not enough voltage to activate the third LED. I'd look for bad connections, or maybe corrosion on the contacts. An incandescent bulb isn't as voltage-sensitive, so it'll work, just dimly, if it's under voltage, whereas an LED needs a certain amount of voltage to work.

 

[Snattlerake]

You are trying the same 3 bulbs correct?

Pull all 3 bulbs from the other bathroom that work in that other 3 light fixture and try them.

I am going with one of the wires on the fixture has been reversed.
Some LED bulbs are polarity sensitive as was stated.

If he has a meter, he can find out. Put the meter on continuity or OHMS.
With the A/C power DISCONNECTED! BOTH WIRES!

Touch one lead to the center of one light fixture then the center of the second. If your meter is on continuity, it will show "0.". and may beep continuously until the circuit is broken.
If OHMS, it will show "0.3 to 0.4" or somewhere in that range.
Now with the first lead still on the first fixture's center, check the third fixture's center. The readings should be the same.

I would then do the same test on the metal sides where the threads are in the fixture. It should be the same readings.

The third check would be just to make sure there are no shorts between the center and the sides

Do all three checks and it will discount any crossed wires.

 

[turkeyrun]

All 3 work
But not with 3 LEDs.
2 LED and 1 incandescent, in any configuration. Contact is being made, bulbs do work.

Fixture is at fault, but where, I have no idea.

I have a bathroom light that had incandescent bulbs, worked perfectly, for years. Changed to LED, nothing works. Put incandescent back in, doesn't work.
Put up new fixture. All working fine.

 

[Snattlerake]

If it were a polarity issue, it should always happen in the same socket, but, if I read it correctly, the LED bulbs will work in all three sockets, just not if all three sockets have LED bulbs in them. To me, that points to a voltage issue, where there's not enough voltage to activate the third LED. I'd look for bad connections, or maybe corrosion on the contacts. An incandescent bulb isn't as voltage-sensitive, so it'll work, just dimly, if it's under voltage, whereas an LED needs a certain amount of voltage to work.

I like this. LEDs use a bit of the voltage to power their circuit and bridge rectifier, which changes A/C to D/C. It could be just enough of a drain.

 

[Firpo]

I think @SoonerP226 is right on the money. Can’t be the sockets as the problem moves. Can’t be a polarity issue for the same reason. Gonna have to break out the voltmeter and see what you have. My guess is either a lose connection in the fixture or a wire-nut or a voltage problem. Could even be a worn out breaker at the panel but that would be down the list on things I’d check.

 

[DavidMcmillan]

I’m gone for the evening now, but I will be trying all the suggestions in the morning. Lots of good suggestions, and I appreciate every one of them.

At least it got us away from chatting about COVID, Congress, Biden, and Post 12’s.

Thanks all, I’ll post the solution!