GMC Repair: GMC 1993 Yukon A/C Parts, blower motor, cold air

Question
I have a 1993 GM Yukon ISLE, and the A/AC does not work, and not to mention I live in texas.UGH! Well there has been a knocking noise that happens periodically, so I thought it was the blower motor and wheel, so I got a new one, still knocks? Knocks even when it doesn't have power so I think that rules out the blower? Or does it? Any ideas on what it could be and what I have to do to make it blower cold air or any air for that matter.

Thank you,
Casey Roach

Answer
First thing with most repair, scan the codes. did the engine light come on? The knocking may not be associated with the blower. does the compressor engage? I live in oklahoma and I feel your pain. email me directly:marvin.saunders69@yahoo.com with your findings.