i have a 2000 tl a/c blowing out warm air compressor making a noise when engaged put a set of gauges my high side is 300 my low side is 20 and suggestions?

 

20psi on the low side is too low. You probably have a leak somewhere in the system...maybe just a small one that takes awhile to leak out. 300psi on the high side is acceptable, especially in your warm climate. Sounds like you need to charge the system with refrigerant. Once charged, the low side should read at least 30...probably more like 40-45 where you live.

 

300 sound a little high to me if you are in fact low on charge. Are BOTH of the radiator/condensor fans on whenever the compressor engages? Is the hot water control valve closed all the way?