Originally Posted by afrohman
When I turn the AC on in my 1996 GMC Yukon, the compressor cycles on but does not cycle off. Still blows ice cold air, just doesn't cycle off. I replaced the AC compressor, accumulator, pressure switch (that plugs into the accumulator) about a month ago.
Hard to say what is wrong with it without any manifold gauge to see what your high and low readings are. Your system may just be a little low on R134a that it does not get high enough for the high side pressure switch to deactivate your compressor.
The best thing to do is to have your A/C system checked with a manifold gauge to get a high and low side readings.
Normal readings on high and low side with AC OFF (static pressure) – Depends on outside temperature, but normally is between 80-105 PSI
Normal low side reading with AC on high speed and MAX & engine at 800-1000 RPM’s – Ranges from 25-35 PSI
Normal high side reading ranges from 200-350 PSI
Good luck and keep us posted.