The low pressure port of the A/C system usually has a blue or black dust cap and is located either on the larger diameter metal tubing typically found between the evaporator and compressor, on the compressor itself, or on the receiver drier (orifice tube systems only). The high pressure service port is found either on the smaller diameter tubing or the compressor and is larger in diameter. Only charge through the low pressure port. There is a web site with a lot of help full information about your auto a/c system check out the link below.
The recharge valve for the air conditioner on a 2002 GMC Envoy can be found by looking at the rear of the engine compartment. It will have a cap over the valve labelled as low pressure side.
The 2002 Chevy Cavalier low side service port can be found on the top of the air conditioner compressor. The low side service port will be labeled as the low pressure port.
The low side service port can be found on top of the air conditioner compressor. The low side service port will have a blue top.
Under the radiator reservoir on the passenger side above the wheel well.
low side port is the one at the compressor
There are two fuse boxes on a 2002 Envoy One under the Rear seat on the drivers side and one under the hood on the drivers side.
The low side port is located on the air conditioner compressor. The low side port will be the entry for recharging your air conditioning system.
The Pontiac 6000 low side air-conditioner import can be found on top of the air conditioning compressor. The low side air-conditioner port will be labeled as the low pressure port.
The air conditioner compressor has two fittings. You can add refrigerant to the low port fitting. The air conditioner compressor can be found on the right hand side of the engine near the front.
The 1993 Honda Accord low side Freon fill port will be on the air conditioner compressor. The air conditioner compressor will be on the left-hand side of the engine.
You can find the low side air-conditioner import on the top of your 1986 Chevy Caprice air conditioning compressor. The low side air-conditioner port will have a blue top.
The 1994 Mercedes-Benz low side port can be found on the top of the air conditioner compressor. The low side port will be labeled as the low pressure port.