I have a 92 100 CS that blows hot air full blast. What is wrong with it and how can I fix it??? It shows that I can change the temp and blower speed, but it still cranks out the same temp hot air at the same speed. The only thing I CAN change is where the heat comes out, and even some times that gets a little weird and doesnt let me. Please help!

 

A common issue is the climate control head. They do fail over time but get a schematic and follow the powers and grounds to and from the climate control head. From what I remember of these units, they were using a version of GM control head. Post a photo of the head for identification.