High pitch buzzing light fixture

[Janet and Todd]

There is an extremely high-pitch buzzing sound when I turn on the ceiling light/vanity lights on in the toilet area and it is very irritating. The dimmer switch changes the sound slightly, but does not eliminate the buzz. The pitch is so high that my husband (Todd) cannot hear it at all -- thanks to his years working around airplanes at Boeing Field in Seattle.

Does anyone else have a ceiling light/vanity light that buzzes? And if yes, were you successful in eliminating that sound? Tell me how...pleeze.

Janet Legg

[wa8yxm]

What type of lighting and yes, it is very common. Depending on the light type.

RV: FLorcesents use an inverter, This is usually a high frequncy (like 400 HZ, just below middle C a few notes) but can be an octave or two higher. (Chromatic scale). (Can you guess my Mother was, and daughter is, a classical musician and I sing in the choir).

LED dimmable and other 12 volt dimmable may use PWM dimmers, and they can also work in a wide range of frequencies.

HOUSE lights normally hum around 120 HZ (About 2 octaves below Middle C) (A below Middle C (middle A?) is 44o HZ by the way an octave is either 2x or 1/2 X that, so that's what I'm basing my notes on, ME Science/Math major and electronics tech,, Got to knwo all this stuff just like musicians do).

[bcbowers]

Janet,

One remedy is to change out the ballast and light bulbs for the large fluorescent fixture in the kitchen with T8 versions. Ours was over heating and humming badly until we went with the T8 setup. We also opted for the highest Kelvin value bulb which provides a more white light as opposed to the slightly yellow versions.

We don't get humming from the 18" fluorescents but have changed those bulbs to a higher Kelvin value for whiter lighting.

[94-Newmar]

Janet, what type of lighting does the dimmer control? Incandescent? LED? IF incandescent changing to a lower wattage bulb will help prevent the filaments from "singing". I've also found changing to bulbs rated for 130volts rather than 115/120volts stops the ringing as the heavier filaments are less likely to sing.

First I would try removing one bulb at a time to see if it's just one bulb or all of them.

[Jim A]

Janet, which lights in the bathroom and vanity area on on dimmers? None of my lights in those areas have a dimmer. The only dimmers in my coach are for the halogens under the cabinets, and the 120v dimmer for the lights on the headboard.

Like Bob I replaced my kitchen 120v fluorescent with a T8 electronic ballast. Mine wasn't humming. I just liked the better light.

I have also replaced the 18" 12v fluorescent with LED strips, as well as replaced the undercabinet lights with LED's for better light. I also replaced the incandescent lights in the vanity with LED strips. Again for better light and lower battery draw when dry camping, not due to humming.

And in case any of you read the recent thread about LED's killing OTA TV signals, no problem with my LED's at all. OTA works fine.

[Janet and Todd]

I apologize for not clarifying that the buzzing light fixture is NOT a fluorescent and there is one switch that turns on both the ceiling light & and over-the-sink light fixture. The one recessed ceiling light is a 12 volt Halogen lamp and the three lamps in the fixture above the sink are 12 volt taillight bulbs (scare light bulbs?). Todd just changed out the three taillight bulbs with three heavier filament lamps...and now the buzzing seems to have stopped. Ahhh! Relief at last!

Thanks everyone for some very good suggestions/advice.

[94-Newmar]

Glad the heavier filaments fixed it.. this seems to be somewhat common with whatever type of dimmers the manufacturers are using, probably el-cheapos :-)

[Jim A]

Janet, FYI the bathroom vanity fixture probably came with three (3) 1141 bulbs in it. These are typically 18 watt bulbs. I assume Todd used 1156 bulbs to replace them. These are 27 watt bulbs. So they are brighter and hotter, and with a somewhat shorter life. The scare lights came with 1295 bulbs, which are 37 watts. Even hotter and much shorter life. All use the same BA15 bayonet base.

Heat, light output, and amp draw is why we often switch to LED's. But good LED's are not cheap. With the design of the vanity fixture and the bayonet base, some LED replacement bulbs won't physically fit in the fixture.

I must live a charmed life. I don't know that I have experienced humming incandescent bulbs.

[Janet and Todd]

So I was in the restroom...resting...and the lights went out. A few seconds later the Hydro Hot shut down. I thought it was a voltage spike so I had Janet go to the Silverleaf and check. Both legs were within normal limits and steady. I visually checked the fuses in the hall and in the wet bay. All fuses were good. Is there an additional fuse block that the fuse for the restroom is located?

[Janet and Todd]

Bobby Vodden found that the issue was an aftermarket dimmer switch had been installed below the sink. The circuit board in said dimmer was overloaded and finally burned out causing the no power situation at the on/off switch. Bobby disconnected the dimmer and all is well.