I have a 2000 Chevy 1500, 4.8L, V8, LS with 225,000. I have put all the mileage on myself and love this old and reliable truck. Last summer, the clutch on my AC compressor was beginning to fail and would need a quick 'tap' with a screwdriver to get spinning. Other than that, the climate control has always worked just fine. Last week, I had an reputable AC specialist shop use all OEM and replace the compressor with clutch, hi-pressure cut-off switch on compressor, accumulator, clutch cycling switch attached to accumulator and orifice tube. The AC turns on as expected (can watch the compressor click on) and the air is ice cold.

Here is my question: Should the AC compressor ever turn on while the AC (snowflake button) is turned off? The AC controls are three manual dials (blower fan speed, temperature and which ducts to blow) and three buttons (refresh air from outside, recirculate air from inside and AC on/off - snowflake). When location for air is selected as 'fresh air from the outside', the compressor comes on when the AC-snowflake button is turned on, and turns off when the AC-snowflake button is turned off. However, when the location for air is chosen as "recirculate from the inside", the compressor is cycling on regardless of the AC on/off button - snowflake being in an ON or OFF position. It did not do this prior to the repair, and I am not sure if it should be doing this. The parts and labor are warrantied for 5 years / 50,000 miles so I can bring it back to the shop, but is there a reason for the compressor to come on in this scenario?

Thank you in advance.

 

Yes the windshield setting. The AC evaporator removes moisture so you're not blinded by condensation on the glass.

 

Thanks Joe! But other than defrost / windshield setting, should the compressor be turning on and blowing cold air through the vents as if the A/C is on (but when OFF)?

 

yes the floor+windshield setting, and any setting with the solid line on it. Other than that, no.
Your owner's manual describes each of the modes do.


Temperature should be whatever you have it set to. Otherwise the blend door isn't working.
But the system still dries the air before heating.