98 Blazer climate control issue
 

Did some searching but I don't think I found exactly what I'm experiencing. My climate control is stuck on the coldest setting, can't get any hot air at all. When I turn the right hand dial to AUTO the ac kicks in even when the heater dial is turned all the way to the hottest setting. Could it be a problem with the temp sensor? other computer problem?

I tried another climate control unit, I originally suspected the cold/hot dial but the other one does the same thing. AC kicks on with the auto setting at all temps.

Both heater core hoses are hot and the antifreeze is full.

Sounds like a faulty temp control door. If no air is flowing over the heater core, it will not get heated.

It started blowing hot instead of cold. Took it to the mechanic, put a brand new door in and a used climate control, no change. I guess its possible that the used unit was faulty as well as the original, are there any other possibilites? Does anything else control the temp besides the climate control dials and the temp control door?

Could be a broken door inside the HVAC case.

How many doors are in the HVAC system?

Four. Three are vacuum controlled and the forth is electronic. The temperature door is electronic and controls the flow of air over the heater core.
http://i11.photobucket.com/albums/a1...7_hvac_sch.gif

and all 4 control the temp? I would think just the eletronic door would do that. I'll get under the hood and check some hoses tonight, maybe a vacum leak?

Where did I say that all four control the temperature...? You asked how many doors there were in the HVAC system and I answered detailing how each one of the doors were activated. Then stated that the temperature door is electronic...

well the guy replaced what I think is probably the electronic door, the recipt says "Temp Actuator." Just wondering if that is what controls the airflow from the heater core because now it wont stop blowing hot air. God I hate this truck.

Thanks for the schematic, I didnt see it at work, photoshop attachments are blocked.

If he replaced the actuator, he only replaced the drive portion of the door. If the door itself is broken, replacing the drive will not correct the problem.