powersmoke

My a/c clutch engages and disengages continuously for about a 10 second cycle while the a/c is off. Is this normal?

caper

I think it has somethig to do with the selector switch if its on any of the defrost modes it causes the compresor to run, someone else should correct me if I,m wrong though.

74dart

I've always been told that the AC was on when in the defrost position. Also if the refregerant level is low the compressor will cycle more.

powersmoke

I checked and it only cycles in defrost mode when the a/c is off.

Thank you.

92DuallyCTD

Sounds correct to me, the a/c should cycle in defrost mode. It does it's job of defrosting(actually should be 'defog' to me...) by supplying less-humid dry air via the a/c system, to evaporate the moisture on the windshield, thus 'defrost'! I'm sure most of us have driven a car w/o air(or working air) and been frustrated on warm humid nights and cold winter days how the windshield keeps frogging over, even with the fan on, right? I think some GM models have the a/c cycle on vent mode too, and even when the a/c is switched completely OFF(sorta like their Flow-Thru Ventilation that never seems to shut off the fan either), I think to acclimate the passenger cab with less humidity. On the other hand, if the a/c continues to quick-cycle when switched on a/c or max a/c, it could be that the outside temps are right at that sweet spot(like 50deg F or less), or you may be a bit low on freon. Hope that helps(but mostly I hope I'm right!), and hope you get 'er done! Good luck! :-)

kd460

Put a gauge on the system (low side) and you will probably discover that your freon pressure is low. You will be able to watch the needle cycle with the on and off cycles of the compressor. Probably need a can in there but make sure you only add to the correct pressures.

Mine did/does the same thing and it was low on freon. Gotta be a slow leak somewhere. KD

058hamer

what is the right psi thats a big can of worms