1996 impala ss air conditioner compressor is very noisy

If the car makes a lot of noise when the air conditioner is engaged there is most likely an issue with the compressor. If I can assist further, reach me at https://www.6ya.com/thericepatch

Air conditioner clutch is going bad and needs to be replaced.

The PCM is located directly underneath the air cleaner assembly (were the air filter is housed.) I have a 96 impala too.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/genevieve_722d20889b4b9c97

you more than likely have a sciezed air con compressor. most modern cars have climate control which uses air con even when demisting and when engaged the electric clutch tries to engage but the pump itself will not turn, clutch will get red hot and burn your belts

Does the noise change or go away if you turn defrost on-which will engage the compressor-if so may be the clutch dragging.

It all depends on the outside (ambient) air temperature. Your A/C low pressure switch is designed to turn the compressor off at 24 Psi. and turn it back on at 45 Psi. Most systems will normally run at between 25 and 40 Psi when the system is running on HIGH blower and "MAX" or "RECIRCULATE". A system that is fully charged may run at 25 Psi when the ambient temperature is 75 Deg. (F) and may run at 40 Psi when the ambient temperature is at 90 Deg. (F). (it can be even higher if ambient temperatures are higher than 90 Degrees.)

To properly diagnose a malfunctioning A/C system, the HIGH side pressure must also be checked. Restrictions in the system can make the low side pressure look normal while the high side pressure is high enough to blow hoses apart. (400+ Psi.)

check air filter and fuel filter. look at spark plugs and wires make sure they are in good shape also.

The Air conditioner compressor is seizing when the compressor clutch trys to engage. When you put on the defroster the air conditioner automatically comes on to take humidity out of air.

This problem sounds like the aircompressor pully, the bearing is shot.
With the engine running and the air conditioner off there is a grinding noise, look at the compressor pully, does it wobble? Then turn on the air conditioner and the noise stops, look at the compressor pully again, the wobble stops? If so that's the problem.

no, more likely a bad blower motor thermal limiter in the blower motor resistor