Nobody has answered this, so let me give you what little info I have.
In a 2007 Suburban, it is controlled by the BCM. Unfortunately, I don't know what year BCM's started getting widely used in GM. From what I've been able to deduce from other questions overtime, it appears from some of the feedback that the prior model Suburban's did have BCM's....so I would guess your Silverado also does.
Hopefully someone in the definitive 'know' will chime in.