This is the third Yukon I've owned. I bought a used 2013 Yukon Denali and the driver-side passenger door started holding water. I thought the swishing sound was the fuel tank, crazy, it was the door holding water like a fish bowl.
First time that has ever happened to me and only one door. IMO the problem is the drain holes on either end of the door. If you look under the rubber trim at the bottom of the door you will see a small hole. This drains the water that might get into the door (how water gets in there in the first place I don't know).
Ok, the holes on every other door are unobstructed. On the door with the problem, it appears to me that the rivets/welds bleed over slightly and impede the drain holes. They are not obstructed with mud or such, it is the welds that are obstructing. It is a manufacturing defect that probably happens every so often, but enough to create a post.
Really disappointed in this problem. I'll take the car to the dealer and see what they think. If they have a different idea I will post it here.