I am curious to know if any of you have heard an intermittent "humming" sound on a 2003 suburban. It sounds like a pump that comes on, and then goes off. I have taken it to the dealership, and they say it is the "brake actuator" priming the pump. It is annoying, but so far hasn't caused any problems.

It "Hums" more while and after towing a camper. I don't know of anyone else who has this going on, so I am trying to figure out if it is indeed "normal" or if the dealership just doesn't want to deal with it.

Thanks