Draft on passenger side of cabin.
 

I have a 2001 1500 Silverado LT 4x4 which I bought about a year ago. When the weather gets cold, I notice a draft coming from behind the glove compartment and blowing straight down on the passengers feet. It's most noticable when the truck is moving at hign speeds. When it's cold outside, this draft is unbearable unless you have on you winter boots and insulated pants. I had the dash apart last night and took it for a drive. The cold air seems to be coming from the joint where the plastic duct work extends into the exterior of the truck just under the windshied wiper on the passenger side. All the foam between the duct work and the body of the truck is in place but the cold air seems to be coming thru the foam. I'm not exactly sure because it is difficult to see up in there.

Any help would be greatly appreciated.

Thank You,