My 99 cad deville "low-refrig a/c off" message is on. added refrigerent, still not working. comp clutch is engaging, the blower is not working. please help possible problem/solution before i give up a

probably overcharged the system and now the high pressure switch is stopping the ac from working
did you fix the leak first

Does the AC system show normal pressure readings and maintains at least 28-32 PSI on the low side charging port?

When you change your oil is up to you,you set the
months & miles you go. Any car with a reminder
for oil is just a gadget

You were told that your low on a/c refrigerant by the
message

Now the check light related or not has to be addressed,
by checking for codes & diagnosing the effected system

Your a/c system needs repair,not added to, only to leak out
& polute the atmosphere

Most likely the switch that is causing your trouble is located on the comp. behind the clutch assembly, In most instences the clutch Assembly will need replaced. The switch engages and disengages the clutch. Most of the time these can not be bought by them thelves.

the compressor may be locked up, make sure that you are getting power and ground to the plug on the comp. and if you are not then the problem may be in the high or low preassure switch, if ther is + and grount then try running a jumper wirefrom the comp. to a ground and one from the comp to the pos. side of the batt. and see if the clutch kicks in and out if it does then run the engine and run the same test and you will be able to tell very fast if the comp. locked up. more often then not it will be a preassure switch

The compressor would have to be working in order for the mechanic to add refrigerant to the system. If he added refrigerant, then the compressor is what pulled it in through the low side service port. He can't say the compressor is cooked, and still charge you for adding refrigerant. The easiest way to find out if the compressor is working is to feel the low and high pressure hoses while the compressor is turning. If it is working the low side hose will get very cold, and the high side, or return hose will be hot. If the low side hose is not getting cold, then the compressor may not pumping the refrigerant. The vacuum hose could be connected to the interior heat/air controls, which could result in no air coming out the A/C vents.

Low pressure switch or pressure sensor.

do an on board self-diagnostic check you should have a ACM 1340 or 1341 code you must clear this code before you can add any freon

Unfortunately for you ( i had the same problem) The A/C compressor HAS to be in working order on these cars or else all heck breaks out with the climate control.

If it's a nice car, get a new compressor installed. If it's borderline- get rid of the car.

I paid 2200 to Cadillac to fix the A/C and climate control only to have the transmission fail in my '93.

I dumped the car soon thereafter....

add freon to low pressure side . low pressure side is large line with small fitting. high pressure line has a large fitting.