1999 Cadillac Deville AC low on dash

NOWRETIRED

MEMBER
1999 CADILLAC DEVILLE
V8
FWD
AUTOMATIC
99,000 MILES

My friend has her dad's car and this summer the ac low light came on on the dash and the ac will now work. I checked pressure on the system and it was withen specks for using 134A I tried shorting the switch in the low pressure line without any results. Not knowing the control system for this car where do I start to check for problems? Any infomation or leads that I can use for help would be appreciated.

Thank You

1 Reply

FACTORYJACK

MECHANIC
4,159 POSTS

Do you mean will NOW work, or will NOT work. If it is not working, what pressure was within specs, there is no spec for static pressure. Based on the ambient temperature, or underhood, a low system can show an adequate static pressure. If you clear the codes, the compressor would probably come back to operation for an undetermined amount of time. My recommendation would be to have the system charge recovered, to determine what amount is in the system. My guess is, it is low. A visual inspection may show oil or tracer dye at the compressor, or in one of the lines. If it is full on charge, you could have a restriction that is pulling the low side toward a vacuum, or a faulty pressure switch or switch connector. A scan tool would almost be needed to view the sensor data.