2002 Chevy Blazer

sounds like a blend door issue,do you hear it chaning over when you turn the control? let me know.

No I don't hear it but have not listened real close. I think you are right, so is it mechanical or electrical.

it is most likely the blend door actuator,so that would be eletrical.get down in the dr/side floor and listen real close while somebody turn the air control knob you should either hear movement or clicking if clicking then actuator is bad, follow noise to find it and remove it.once you get it out turn the rod that it was connected to to verify that the door does open and close.let me know.

Thanks I will try to get to it in the next few days. Really appreciate your help.

your welcome,we're here if you need us.