IS300 compressor runs but does not seem to pump and its not cooling. Pressure on high side 165 lbs, low side at 150 lbs but drops to 125 at 3000 rpm. No leaks in system. Is compressor shot or is this a relay problem?

 

its shot!! happend to my uncles hummer

 

if its actually turning and your high side pressures are low (less than 200) and the low side pressures are high (greater than 50), then your compressor is dead...

 

I have seen some rebuilt ones for sale on the sc300 classifieds