For two months I've noticed a sound as I sleep at night. It sounds like a muffled jake brake and it cycles over and over from high pitch to low. Since I've been in an RV park across from the Long Beach Ports, I actually thought it may have been the trucks that service this area 24 hours a day. But, I moved the coach this weekend to a quite locations and guess what, I woke at 3:00 AM thinking I had brought the trucks with me. I turned off every breaker in the coach and the sound did not go away. I was plugged into 50 amp power and the inverters were on but I couldn't tell if they were the cause. Any ideas to keep me from going completely nuts?

Richard Barnes