I have a 99 jeep cherokee classic. I have a problem where the A/C clutch does not engage at all. I can manually engage it by manually engaging the A/C clutch relay in the relay box under the hood. When the clutch is manually engaged by manually closing the A/C clutch relay, the A/C blows cold air. I checked the 20A fuse for the A/C clutch, also located in the relay box, and it is OK. I checked the relay itself to insure that applying 12V to it would cause it to close, and it appears to be OK (it does not appear that the relay itself is bad). I looked at the control unit in the interior (containing the knobs to control heating and A/C), and it appears that vacuum is used to control heat and A/C function when the knob is rotated to that A/C position, but I can't determine yet how the vacuum system ultimately manages to close the A/C clutch relay. It seems that 12V is not being applied to the A/C clutch relay for some reason, and I have read that there is a pressure switch on the system somewhere. Could it be that the refrigerant is low, even though the system blows cold air when I manually engage the relay? Also, is there a vacuum switch somewhere (under the dash, etc) that is actuated by vacuum when the control knob is rotated into the A/C position, that should be ultimately actuating the A/C clutch relay? Any help would be appreciated. Help! Thanks.
- posted
17 years ago