Great site and great write up!
I fell upon this from a cross post on GM-Trucks.com. Having the same issue with my step dads 2004 Silverado with the dual automatic climate control. A while ago the passenger side would start switching from heat to AC and back again all on it's own at random times (needless to say mom didn't like the AC on their 45 minute ride to work in the winter when it was 20 degrees outside

). Anyways, about 3 weeks ago the a/c completely went out, compressor and all. I hooked up my gages and added some freon to it...compressor kicked back on, and it sucked down a whole can of freon. Wouldn't you know, passenger side started blowing ice cold again, and the drivers side continued to work fine. Being new to this dual auto climate control mess, I thought ok...maybe that was the sign that the freon level was low......or so I thought.
It lasted about 3 weeks, and now the passenger side is blowing cool (luke warm), while the drivers side for the most part stays cold...but seems to hint at trying to blow warm at random times. I checked the freon level again to make sure we didn't have a massive leak, and it's still good.....so I guess that leaves the bled door actuator?
Now that i'm done with this long post, for those with the 04's with the same set up, did this write up fix your problems? If it just involves putting a new actuator in, i'll tackle that in no time hopefully. If it did fix your problems, how did you get the temperature down with out destroying the new actuator? Set it to 60 before removing the old one, that way it's still on 60 when you turn the ignition on with the new one in?
Thanks for helpin a Jeep guy out....still learning how these Chevy's work...and not used to all this fancy automatic equipment :)
FYI, in case it matters, the truck has 116,xxx miles on it (all highway).