2004 Bonneville - No air flow to defrost or floor

[reedj66]

Greetings from the fine state of Louisiana!

My 2004 Bonneville will only discharge air from the mid level vents (dash in front and out of console in rear). It does blow hot when set to heat and cold when set to cold. However, if the floor vents are selected the air still comes out of the dash vents.

Lovely.

If front defrost is selected, a nice blast of hot air hits me in the face.

Beautiful.

I'm an "experienced amateur" at car repair so I'd like to tackle this myself. Thanks in advance for any advice and help!