The low-pressure port in a 2003 Chevrolet Impala is the port where refrigerant is added to the air-conditioning system. This port is TIG-welded to the top of the aluminum low-pressure line and covered with a blue plastic dust cap. The dust cap prevents dirt and contaminants from interfering with the low-pressure port valve. It also prevents something from accidentally depressing the valve stem and inadvertently evacuating refrigerant into the air. Refrigerant must be recovered and evacuated by a licensed facility and never released, accidentally or purposely, into the atmosphere.
Shift the transmission into park, apply the parking brake and open the hood.
Stand in front of the engine, looking toward the windshield. Look straight down and locate the two aluminum lines coming off the right side of the air-conditioning condenser.
Look at the large diameter line; this is the low pressure line. Follow this line back toward the firewall approximately 12 inches. The low-pressure port is covered with a blue or sometimes black cap with an “L” stamped on top.
Unscrew the cap to expose the low-pressure port.
