I only have air conditioning in the winter and have only heat in the summer. No matter what I do with the controls I get the opposite of what I need. When it first started I could get air by not having it on full, then it was opposite no matter what I did. Any ideas?

 

Better move to the opposite hemisphere! Seriously, what year, model, engine, and is the A/C manual or automatic climate control?

 

It's a 1999 4x4 V8 Blazer with automatic climate control.