I have the automatic A/C system in my 2000 blazer. Every time I turn the fan on for the heat or AC the motor screams. I am shopping for motors but I am not sure which ones I need. I see the ones listed w/ ATC, which I think is what I have, but I am not sure.

 

I think you have the correct replacement; ATC = Automatic Temp Control. Actually I would not think there would be a difference in blower motors between the two HVAC systems....but guess there is.