Expert: autohelp - 8/2/2009

Question
QUESTION: My 97 SLS with Northstar engine flashed Lo refrigerant several times then compressor cut off.. took to my mechanic.. did vac. pump and then added freon... A/C compressor remained off except for intermit. cooling with Auto setting...  Did homework and removed codes as described... recheck freon levels, seems OK but A/C compressor refused to come back on... can you help us figure out what is going on to get the compressor to kick back in full time... not just intermitent when in auto.. Thanks in advance...Tom,Jr.

ANSWER: The A/C compressor will always cycle ON and OFF. It will never run all the time. Are you getting sufficient cold air in the vehicle ?.

---------- FOLLOW-UP ----------

QUESTION: Am not getting sufficient cold air.. am getting a short duration of cold air into the vehicle, then it cycles quits... if its 85 outside, can set temp to say 70, it blows cold for say 10 secs, then just blows air for a while (say up to a minute or more) then another short blast of cold air... cannot override the auto set to get a constant blast of colder air... prior to problem, it would blow cold until it reached set temp then cut back... again, any advice for the helpless.... Tom,Jr.

Answer
I really need to know what your HIGH SIDE & LOW SIDE freon pressures are reading when the A/C compressor is running.

By jumpering the A/C compressor RELAY you can keep the compressor running for 2 to 3 minutes without it turning OFF.

I would suspect that you may have an orifice tube restriction and or a freon leak .

Is the LOW REFRIGERANT (freon) Light still coming ON on the dash ?.

Do you have ANY codes at all ?.