ABS and AutoTrac lights stay on

Sound varies directly w/ speed,exactly. Never services PTU lube, have 106K miles. Noise is getting louder, is not tire noise. Too loud for a luxury name vehicle! Changing both rear bearings today with concern for this being final fix. I drive approx 600 miles per week. No Leaks at rear observed. Thanks.

was traveling and found windows down next morning at motel. it was definitely not human error

I just purchased this vehicle - also how often should the brakes be changed?

Where is a/c filter? Is it easy to replace? How much do they cost?
My dealer want $55 to replace mine...I told him to take a hike.