2003 Chevy Trailblazer can't get air out of top vents?

[Matt K]

Have replaced A/C-heater controls still can't get air put of top vents. comes out at feet and defrost only.

[harperboy1]

----faulty/shorted hvac mode door actuator motor--very common problem on 02-04 trailblazer,envoy,and ascender.it is mounted on the driver side of the hvac module above and to the right of the accell pedal--replacement comes with new gear.and it is a bad bad bad mother to replace--hire a contorsionist to perform the work.good luck!