My 2012 ram 1500 5.7 recently threw a couple of codes for cam position sensor..changed that today and while test driving it did great but I noticed a his under dash while decelerating that stopped when I pressed the pedal again

 

Is anything in there vacuum powered? A/C vent controls?

 

I'm pretty sure everything is electronically controlled under the dash, but I've been wrong before.

 

That's what I thought too, maybe brake vacuum booster? As I think it vents inside the cab??

 

That or vacuum line under the hood and you can hear it in the cab.