I have a 2007 Ford Fusion AWD and noticed a humming noise as I was driving last night. It started when I got near 50mph and seemed to stop or get so quiet as to be not noticeable when I got to 40 or put the breaks on. Does anyone know what this might be? Thanks!
If the pitch/volume of the noise changes when the steering wheel is turned off-center (i.e. changing lanes), one or more wheel bearings may be going bad.
In addition to a bad wheel bearing (or two), the humming noise could be coming from the tires.
Many tires that were previously quiet will become noisy once they have a significant amount of tread wear.