Which port on AC compressor is low pressure 1999 Chevy blazer?

On a 1999 Chevy Blazer's AC compressor, the smaller diameter port is the low-pressure port. It's usually identified with a smaller fitting and sometimes a blue cap. However, always double-check your vehicle's specific AC system diagrams or your repair manual for absolute certainty, as there can be variations. Relying solely on size or color can lead to mistakes.