That would be new news to me if they've started shipping them with powered/heated mirrors. There should be a seperate controller somewhere on the dash to allow adjustment. And I'd think it would be on the LH console.
Similar to this Georgetown.
I have thought about swapping out our mirrors to powered/heated ones when we first purchased our RV, but I'm not sure its worth the $2-300. So many other upgrades in front of this one. Maybe someone with a 32DS will chime in. Also, since they typically do changes mid year, an early 2016 32DS might not have it vs a late 2016 32DS...