I have a 1993 with only 26,600 miles. 3L Auto, and A/C. The A/C clutch is always cycling no matter the position of the controls.
I have checked it out this morning, and I confirmed that with the heater controls all set to OFF, (lever, fan switch and a/c on/off), the clutch still cycles on and off. I pulled the a/c relay in the Power distribution center, which of course stopped the cycling.
The motor rpm increases slightly as the clutch engages, as it should, but What is causing the a/c to be continually on?


Iain

 

It might be designed to operate that way. Check the owner's manual.

 

if its cycling chances are its undercharged. the sensor senses a certain amount of ambient pressure in the lines, the compressor kicks on to bring the pressure to where it should be, then kicks back off, then kicks back on again when the pressure settles, and again the sensor picks up that it is not within specification. and the cycle just keeps repeating. but for it to run the compressor with the heater on is normal for dehumidifing the air for you when its cold and raining.

 

Is there a separate button for the A/C on the Control Selector Assembly? The actual switch inside associated with the button could be failed "closed". Also, keep in mind that, when Defrost is selected, the A/C switch is likewise engaged.

 

This problem just came up in the last week. I know it worked correctly before.
The only thing that seems possible so far is a bad switch, or a bad relay.

Iain