nealinator· SS-Guru 🏅TOTM, HowTo Author,🥇Mbr Extraordinaire,
2010 GMC All Terrain 4x4 5.3 LC9 211k mi
Do you hear air blowing when on defrost and floor? Is it still coming out of the front vents or what? Some additional details will help. Have you watched the cam movement mentioned by Dave above? Are you sure you got it correctly re-connected? That cam can be tricky to get back in the proper detents to drive the doors.