How do you know if 03 buick rendezvous is using awd ?

I just bought one and it snowed pretty heavy last week it did great but i did not see any type of awd light on or does it atomaticly just come on with no light



also when im driving i hear a odd humming sound my mecanic said it was a hub unit spent the money still making the noise sounds like all tires are making the noise could be just the tires that are on it.How do you know if 03 buick rendezvous is using awd ?Buick's AWD is an "always-on" system, unlike 4WD, which is an "on-demand" system. And AWD tends to be more reliable, since it never has to engage or disengage. Less parts to break than most 4WD systems. :) So don't worry. AWD is ALWAYS working to keep you in control. :)