Noise coming from the water heater under kitchen sink

Hi everyone, We just came home from a weekend trip and have noticed a high pitched ringing coming from under the kitchen sink. It seems to be coming from a little white box that is attached to the side of the cabinet next to the water heater. We have unplugged all power to the trailer and disconnected the batteries and it still rings. Has anyone had this happen or heard of this? Thanks your answers!!

Sarah

Hey Sarah, Can you post a pic of the thing that's making the noise? Does it do it all the time?Or does it do it only after heating the water.

Mel

I can post a pic of it tomorrow. It just started sometime today, when we parked it last night it wasn't make any noise.

If it doesn't turn out to be the box I have heard that the water heater elements will produce a ringing noise if not put in the correct orientation in the tank. By that I mean, that the element either needs to be horizontal or vertical. I can't remember which produces the ringing. I found it somewhere on the net last year when I replaced my fried element.