1998 Volvo S70 GLT, 130k. My ac was blowing warm air so i added can of freon and can of uv and freon to find out if its just low or leaking. It was ice cold for few days and now compressor goes on and off every 2 seconds. Air is warm as you can imagine. I couldnt find any leaks on the lines, drier, or compressor itself. I wanted to add more freon but my gauge shows that system is full. I am little confused now. System is full, compressor doesnt stay on for more than 2 seconds at a time. What am i looking at here?
thanks!

 

If it were me, i would ck voltage is passing thru the both the high and low pressure switches.

According to your gauge, does the low side pressure go down when the compressor engages?

 

You could be low and still reading close to 40 PSI or so. You might be low.