I have a 1998 Blazer 4.3 that recently if driving in town the AC blows hot air, but if I'm on the freeway it will keep moderately cool. I've made an attempt to add freon, but no changes. Compressor is engaging properly and system blows as expected. Any ideas, thanks. Rich
Optional Information:
1998 GMC Blazer 4.3
Already Tried:
Add freon