Auto Air Conditioning & Heater Repair: AC vent problems

Question
I have a 2001 Chevy silverado 2500 the ac doesn't blow through the dash board vents when set on that setting and only works on the floor and defrost settings. how can I fix this? Or what can this be?

Answer
Hello Andrew
It depends whether you have full climate control or just refrigeration
Full climate control will have a temperature display that you can preset

This determines whether the vents are controlled electronically or by vacuum or cable
Full climate control systems may have a self diagnostic function that you can access yourself by pressing a combination of heater control settings.You may find this by a search through Google

I do not have access to this information as we are UK based
If it hasn't, it could mean a trip to the dealer who will plug it in to the manufactures diagnostic machine.
A vacuum or cable operated flap or door system should be easier to diagnose.

Let me know which you have and I can help you further with a manual system

Regards
Paul