Cracking noise every time i brake!!

I just bought a brand new chevy silverado 04 currently going on 750 mi. I used to own a 02 silverado never had major problems with it.

Every time i brake there is this craking noise form inside the cabin, i`ve been alble to locate it its coming form both doors. Any one have a similar problem.

Also AC system is "hizzing" and making noises all the time i`ve put it on diffrente modes still same problems.

I would greatly apreciate any help...

thanks..