When air conditioner is turned on does the light stay on or just flash and go out when you turn it on ?

 

It SHOULD stay on. Blinking and or blinking/going out indicate a low R-134 charge. When you press the AC ON Button, the AC Compressor Clutch "center hub" should engage with the drive pulley and not turn ON and OFF, The low side pressure and high side pressures with the compressor off should be equal (approx the same pressure as the outside temp. (Good rule of thumb).

With the engine running (clutched engaged) the LOW side pressure should be right around 32-38 lbs. (NOTE- 1) Low side pressure reading has many variables that effect the exact correct pressure. They are; Outside temps, Humidity, Engine RPM, Interior temp. Blower motor speed.

The C5 GM Service Manual has a very good chart that should be consulted for a more defined list of high and low side pressures.

(Note-2 ) Most of the refringent leakage issues results from minor leakage from the high and low side charging ports. Leak check those if you recharge the system.
Make sure that you get the correct refringent R-134a and only charge at the LOW PRESSURE Port with the refringent can in the UP-WRIGHT direction. You can put the can in a pail of hot water while charging to help turn the liquid in the can to a GAS for faster charging. Only take a system pressure reading with the can valve SHUT.

Bill

 

thanks tried to recharge the air conditioner but won’t take a charge! Does the compressor have to come on before it will take a charge? Hate to take it to the dealer but it is looking like I will have to. Car is a 1999 with 14000 miles.

 

If it wont take a charge you need to have it evacuated and refillled. no need for a dealer, any ac shop can do it.

 

Pretty low miles on it. Did you use refrigerant with a gage? If not you should get one with a gage. I would use freon with a lubricant and maybe dye. If you can't build enough pressure with the can connected the compressor won't come on. You can jumper the low side switch to allow the compressor to run. That will help suck the freon in. If you feel the can getting cold then it's sucking the freon in. Don't run it too long if it not taking freon because you might damage something.

 

added 2 cans of refrigerant and yes it had a gauge seems to be working now. If it stops again then I will check for a leak.

 

Just a word of caution about jumping the compressor to pull in charge. If the system has lost its charge it is now filled with air at atmospheric pressure. That atmospheric air also contains moisture. As a contamination a sealed R134a system, the air will cause the compressor to run at a higher discharge pressure which will negatively impact compressor life and probably increased compressor noise. The free moisture may lead to internal corrosion as well until it gets absorbed by the desiccant in the accumulator dehydrator.

One other caution; if you added two 12 ounce cans of R134a, you are just 2 ounces shy of the 26 ounce factory charge. If your system was nearly empty, 24 ounces is fine to add. On the other hand, if your system was down to say a half charge of 13 ounces and you add 24 to it. you are now overcharged. Overcharge is also not good for the life of the compressor and it will significantly impact your cooling.

 

the compressor wouldn’t work so it must have been fairly low not sure how much would be in the system if the compressor won’t run. Anyway thanks for the info.

 

Different year C5s have different fill volumes. Some are 28oz, like my 2000, which takes 1.75lbs (28oz), and some 26oz. Using a scale to weigh the amount you recharge the system with is the best way to do it. BUT-You should evacuate the system FIRST. To do that, youd need to rent a free pump from Auto Zone, or whoever, or buy a pump. I bought one. Anyway, then hook up a vacuum pump to the low side/fill port to draw out all the moisture and any remaining minute amount of R134a. Then add, by weight, the correct amount of refrigerant. However, if you have a leak somewhere, you'll soon be back where you are now. You also have lost some PAG oil. Every time you recharge, you will have lost more oil. Lose enough, and your compressor will take a dump. Best to fix the leak FIRST. I'll tell you my situation. I have a small leak in the evaporator (SUCKS!!). But not all my 134a leaks out. It gets down to a certain point, and quits leaking. Of course, the "certain point" isn't enough to cool the vehicle much! I'm leaving it alone, because I just put about $2500 into a new compressor, condenser, accumulator, and hoses/pipes. Since I still have a small charge, enough so the light does stay on, no moisture is getting in. If I keep recharging, I'll eventually run out of PAG oil, and my new compressor warranty will be toast. So I'm leaving it alone until I can gut the whole front of the interior near the end of Summer/Fall, and replace the evaporator.......