High pitch sound

[Irish Mist]

Hi Everyone
I have 2011 R29 and I am getting a high pitched shriek off of something that stops before I can locate it.. Seems to be from panel area. Not sure it it might be propane sensor or CO2 sensor. Nothing all day then it just happened again.. Seems to be when the A/C is on.
Any one else have this and know what it would be? Only lasts for maybe 2 seconds

Thank you for any help

 

[Irish Mist]

Does something in the panel make a noise if the power drops too low? Just noticing with the A/C the reverse polarity lights are dimly on .. if the water heater is on as well ( 0nly hooked up to 30 Amps ) turn either off and the lights do not glow any more. Just strange doing everything the same as we always have here. This noise is something new.

Thanks for any thoughts