On the low side of the system which will be on the a/c accumulator that is located on the passengers side next to the evaporator close to the firewall......
Using the proper type of freon and a gauge, connect to the low side ac port. With the engine running and the ac on high, add freon till the gauge shows full.
Because they no longer use freon.
You add freon to the low side fitting,top front,on the ac compressor
You call a licensed contractor and have them check your system. If they determine that it needs freon, they can add the right punt.
Add freon
R134a
there is a high pressure switch on the line or the accumalator, unplug it and place a jumper wire into the connector
R-134
R134a
R12-if it has ac of course.
Freon is added through the ac low pressure port. The port is located on the aluminum pipe on the ac line.
ac drain stopped up,ac is low on freon