Same problem Low Refrigerant, Compressor off, try to recharge with r-134a but it always has the pressure at over 80psi.  so I bleed it, and within seconds its in the red again.  I think the main problem is that it will not turn the a/c on when i am trying to recharge probably b/c of the compressor being turned off because of the low refrigerant.  Any ideas of how to recharge the a/c?   it is a 97 Cadillac Seville SLS

I had the same problem. The thing is you need to have the air on while you're recharging it and the compressor won't turn on. I was able to recharge the air by disconnecting the positive battery cable and reconnecting to reset the computer and immediately have someone inside the vehicle turn the air on before the computer can recognize that the refrigerant is too low and disable the compressor again. This will allow for the compressor to turn on and for you to recharge the air. Make sure that you have the replacement refrigerant connected before you turn the ac on so the refrigerant goes in and keeps the compressor on before the computer catches it again.

I had to take mine in to get recharged and they had to reprogram the compressor to come on.