AC cycling on & off

[hump]

I had the hood up and noticed the ac clutch cutting in for probably 5-10 secs, then out for 20 or 30 secs. I know they cycle on occasionally to lube bearings or something but this seems excessive. Engine was warm and temp outside was maybe 40 deg. F. I pulled the fuse and this stopped. Is this normal, and will it still occasionally cycle with the fuse pulled. Not much need for AC here for the next 7 months. (that's if we're lucky)

[Scottpearce]

Did you have your defroster on? The compressor is used to dry the air when the defroster is selected. This does two things, one- it helps clear the windshield faster do to the dry air, and two- it keeps the compressor and a/c line seals lubricated through the winter months.

[diesel65]

Hi,
As what Scott said, did you have your defroster on, or did you have the a/c button pushed in even though you have the blower switch off.
The compressor should not be on unless you command it on.

I have seen alot 97's thru 99's blower switch are bad, GM's brilliant engineers decided where when you turn the blower off, the switch will turn on another circuit to turn off the compressor.

To make sure the compressor won't come on leave the a/c button out or don't leave it in the defrost mode.

The rapid cycle is normal in colder weather, you have to understand Pressure to Temperature relationship.

The lower the temperature, the system pressure will be lower, the low side pressure switch cuts out around 20 to 24 psi.
For example the old refrigerant R-12, at 32 degrees the system pressure will be 32 PSI.

Happy Holidays

[hump]

I didn't think about the defroster. I keep it in the defrost/floor setting. The ac and recirc button are both out though. The compressor kept running full time about a month ago and when I pulled the fuse it kicked out. GM tech told me that sometimes a relay sticks and causes that, and several sensors control compressor. That hasn't happened since, but I'm wondering about the seals if I keep the fuse out. Will the compressor run intermittently with that fuse pulled? My truck is a 97 Z71 1500. Thanks for the input.