Passenger Side FOOTWELL air leak

[Moosemoon]

The Yukon was returned from the original refurb debacle with the front heater fan incorrectly installed. It was replaced - also incorrectly - so we did it ourselves. Works great now. HOWEVER, there is an air leak under the dash on the passenger side. Don’t know if it was returned from the refurb that way or if it was messed up later. Heater blows hot but can’t overcome the cold air coming in. Any ideas?