Where is the low pressure port on a 1999 GMC?

1999 Audi A4 Quattro Avant

The Low pressure A/C refrigerant port

The High pressure A/C refrigerant port

the low pressure port is usually in the accumulator (aka receiver/drier) which is the large silver cylinder on the passenger side. If its not there, sometimes it is on the a/c compressor on the marge diameter hose/line. The high side is on the smaller line near the coolant reservoir. The low side is the one you want to fill with.

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The low side port of the 2005 GMC savanna Van is located on the low pressure side of the compressor.

This is found by locating the compressor driven by a belt that has a clutch that engages and disengages as the a/c cycles.

The low pressure piping is always in the larger diameter piping, and the high pressure side is always contained in the smaller diameter piping.

Therefore, follow the thick pipes from the compressor up to the accumulator, which looks like a large can of soup. On the accumulator receiver/drier is a port that connects to the tube that is connected to the can of r134a freon refrigerant.

Simply quick connect the tube to the low side port, which is located on the 'thick' tubing or on the accumulator and then fill until the low side pressure is 25 psi to 45 psi while the compressor is running.

When the car is off and the compressor is not running, the pressure should be 75 psi to 100 psi on a hot day.

Hopefully the system doesn't have a leak slow or fast in it.

the large ac line is the low pressure side the port is between the compressor and the firewall this is where you charge from

There is no A/C drain line. The A/C refrigerant is removed or added by way of the low pressure port. The low pressure port usually has a black or blue cap with L written on the top. Find the large diameter tube leading from the compressor back to the firewall. Sometimes the port is on or near the compressor or on the accumulator neat the firewall and is not on the large diameter tube. Make sure you have the low pressure port. Connect to the high pressure port and the can may explode so make sure you have the correct port.

low pressure is port is alway next to the a/c dryer up on top the small port

well it sounds like you have too much freon and or oil in the system you need to have it evacuated and vacumed down and fill with exactally what it calls for and you need to also check the action of the fan make sure enough air is comming through the front of the car

look for the large ac line/hose and follow it untill u come to the small service port this is wher u charge the small ac line/hose has the large port this is the high side

if it is low on freon the compressor will have 0 volts becuase the low pressure switch on the evaporator isn't triggering...if you have freon then replace the low pressure switch...take a small piece of wire and disconnect the low pressure switch and jump the two sides of the plug together...compressor should come on

the low pressure port is the charging port, this port is either in the low pressure line or the accumulator that the low pressure lines to to (can shaped object), the low pressure line is the larger of the two lines from the compressor.