Hey folks, 2013 f150 Fx4 3.5 ecoboost. Getting a power steering type of whine. Only happens when the compressor is engaged. Noise increases with throttle. I've read other posts on the subject. I only get the noise when ac compressor is running. As soon as I switch to just heater the noise subsides. Ac blows cold so it seems to be working. 3.5 eco doesn't appear to have a idler pulley. I'm thinking it's may be the bearings in the compressor pulley?? Any advice would be greatly appreciated. Thanks. Truck has 30000 miles on it.