Auto Climate control not woking-need a good reference manual!

2000 Jimmy SLT with auto climate control, hot air no matter what I do with the Temp control. Mode selector works fine, and air comes out of the proper point when I change from vent to blend to floor to defrost, so that part is working fine. I am certain the problem is in the Auto climate control, which I have determined is electronic, not vacuum or cable driven. I know that there is a "device" that controls the air flow across the heater core before it enters the cab, but I have not found a good manual to help me locate all the parts of the system to troubleshoot and replace any faulty components, just a bunch of piece meal references. I signed up with ALLDATADIY and got the most out of this sight, but there is really no "A-Z" step by step procedure that breaks down the system. The Haynes manual simply states that the "Automatic climate control system is too complex for the do-it-yourself mecahinic and not included in this manual." I am an engineer and take insult to that, but it doesn't help me in locating the reference manual I need to fix my problem. It would be easier to just put it the hands of the dealer and say fix it, but at $86 an hour, I hesitate. Any suggestions?

Blending door is stuck or faulty or the connection to the temp controls has failed.

I get that part and agree with the diagnosis, but I still have no reference manuals to tell me how to get to the part or trouble shoot the system.

Get in your truck and look.

What the hell doe that supposed to mean. I bought the Haynes manual per your reccomendation and as good as it is in detail it specifically excludes the Automatic climate control because of it's complex computer control. Ther has to be some manual out there that addresses this system in detail.....

What I was trying to tell you is that you will have to go and inspect your blending door and trace it back to the control panel.

Just look for some loose connections or vacuum hoses.

Looked in behind the glove box.....not much to see. Will have to wait now as Jimmy is in the body shop having the damage repaired after hitting an 8 pointer Thanksgiving day.