High pitched sound from breaker.

[Lminnes73]

I have a high pitched sound from a select breaker. When the breaker is off, the noise stops. Unfortunately, it's the breaker that controls the plugsand lights in the master and the bunk house as well as the tv. I have a 2010 Jayco jay flight g2. We have a brand new battery.

[BuddyRay]

Hmmm - are all the LED lights working? I've never seen it in an RV - but I have seen a problem in home lighting where the tiny circuit in an LED light goes bad. These circuits reduce the 12v DC down to 5v DC usually by using an oscillator (called a switching power supply) to switch the current on/off really fast and then use a capacitor to smooth out the current again. These circuits need a filter to keep the oscillations from getting back into the powerline. Early LCD's didn't have those filters and as a result used to play havoc with electronics (like TV's and Radio's) on the same circuit. I wonder if you have a bad LED light that is causing the sound.

[us71na]

Is your 12 volt converter on that circuit? Converters are known to make noise.

[eldermike]

The converter uses PWM (pulse width modulation) to regulate the voltage. This can be a source of this type sound. Most often the sound is only heard when there is no load on the circuits like at night when everything is turned off. This is due to the frequency dropping into an audible range. It's normally way above human hearing range. Try plugging in something like a drop light or hair dryer and see if it affects the sound when it's switched on.