06 Libby 3.7 AC compressor cycles at all times

[fredred]

While doing a coolant flush on my 3.7 06 Liberty Limited, I realized that even though the AC control was set for MAX heat, and the amber compressor light on the dash was off, the AC compressor was cycling as it would with the AC set to "on". I've had this Libby for a few years, and never had any AC or engine work done, but I'm either the 3rd or 4th owner. I'm concerned that if the compressor operates in freezing temperatures, it may damage the compressor or other AC components. I'm guessing a prior owner mis-wired the connector, and the compressor clutch is always getting a hot feed while the ignition is on, instead of from the dash switch. Has anyone encountered this before?

 

[turblediesel]

The AC runs in most heater modes to help dry the air and dissipate moisture in the cabin. There's a chart somewhere in the service manual that shows what's happening in each mode. There are settings when the AC is definitely off but I'd be guessing which without the book in front of me.

 

[LibertyTC]

My 04 KJ climate control may be similar to this:

You must be registered for see images attach

 

[fredred]

Thanks for that diagram. My AC compressor cycles even when the dash knob is in any of the 3 positions with the red asterisks indicated. I'll need to check a wiring diagram to try to figure out why.

I rechecked my Liberty and reread the 2006 owners manual section on AC operation; here's the result: above 30°F, the compressor is always operating when in "Floor", "Mix", and "Defrost" modes. In "Recirculate", "Panel", and "Bi-Level" modes, the compressor only operates when the snowflake button has been pushed and its amber light is illuminated. I also have a 2007 Liberty owner's manual, and it indicates that in "Mix", and "Defrost" modes, the "Snowflake" button would have to be depressed to turn on the compressor. Maybe Jeep liked to confuse people by changing the operating parameters from year to year.

 

[SkyJeep]

I read somewhere that the compressor is engineered to come on throughout the year to keep the AC system internals lubed. Sounds plausible. On my 2006 it runs for several seconds then turns off for a few minutes.

 

[sota]

skyjeep is correct.
of course it's the reason why my compressor clutch died at 90k miles. I now just unplug the clutch when the colder months come.
also prevents the evaporator from freezing over in the winter, thereby denying me any HEAT in the passenger compartment!

 

[JeepJeepster]

My 2004 only turns the A/C on in the two defrost modes. The 2005 will also turn the A/C on in the floor only mode. You can take part the controls and put tape over the contacts so it only turns the A/C on in the modes you chose to not put tape over. I bought some 2005 controls so I could control the A/C separately from the dial selection and put tape over all positions except the pure defrost mode.

Its pure stupidity to have the A/C run in the middle of the winter.

 

[KJowner]

My 2004 only turns the A/C on in the two defrost modes. The 2005 will also turn the A/C on in the floor only mode. You can take part the controls and put tape over the contacts so it only turns the A/C on in the modes you chose to not put tape over. I bought some 2005 controls so I could control the A/C separately from the dial selection and put tape over all positions except the pure defrost mode.

Its pure stupidity to have the A/C run in the middle of the winter.

I find mine steams up without the AC in winter.