Auto Air Conditioning & Heater Repair: 1999 Sunfire GT Heater, unhooked, actuators

Question
When I turn on my Sunfire's heater it won't switch between defrost/floor/front vents, it just constantly blows from all three. Is something unhooked or does something just need to be replaced? If you could help out it would be greatly appreciated!

Answer
NUMBER ONE PROBLEM WITH THIS TYPE OF SYSTEM HAS BEEN POOR VACCUM. IT CONTROLS THE ACTUATORS IN THE DASH THAT CONTROL THE DOORS. CHECK FOR THAT FIRST. THE VACCUM SOURCE COMES FROM THE ENGINE AND A SMALL LINE FEEDS THE DASH THRU THE FIREWALL.

GOOD LUCK