Pontiac Repair: Computerized AC unit blows hot air, vacuum pressure, ac unit

Question
I have a 1998 Blazer with a V6.  The HVAC is computer controlled, the compressor is functioning and the accumulator is cold.  Have the settings to Auto Fan, Max cold air and Auto venting.  AC unit blows heated air.  Changed it over to max heat and the venting changed from dash to floor (meaning the controller was working).  Pulled the RDO fuses and let it stand for at least a half hour.  System did not seem to recalibrate after fuses were returned and key turned on.  Verified there is vacuum pressure.  Outside air and vent diaphragms are working.  Cannot find the hot/cold air diverter.  What is left to check?

Answer
Hi Mike:
weel the problem is either with the control head or withe the temp actuator on the HVAC box. chances are the actuator is bad more than anything else. The actator is loacted on the top HVAC box behind the glove box. Without the use of a scan tool to see what is going on with the temp door. My guess is the temp door actaot os bad or maybe the door is binding. if you take the actuator off the HVAC box see if the door will move from full hot to full cold. You could also have a temp sesnor inside the HVAC box that is bad making the door move to the luke warm position it's stuck in now. Again without a scan tool it's hard to say for sure what's going on...