1982 300sd
fixed my a/c comp problem. want to re-charge. can't seem to find what the recommended high - low pressure readings should be.
also can anyone tell me if the air supply ducts/control valves have any affect on a/c performance.

thank you in advance

flyboy

when i do it i just use the color code on the guage...

green, yellow and red...

Did you open the system (remove hose or switch) and release freon or are you just trying to top off? R12 or R134 in the system? they have different pressures.