A/C clutch stays on?

[Mahilly]

This problem just started a couple weeks ago. If I run the fan for outside air, the a/c will be on and blowing cold even though the AC button is turned off. The a/c clutch just stays engaged if the fan is running. If I turn off the fan, the clutch then disengages. I turn the fan back on, the clutch will re engage. I have cycled on/off all of the various options for a/c, max a/c, recirc, etc. I have checked all of the fuses and tried resetting the entire system by unplugging my battery. Also checked for OBD fault codes. Does anyone know what would cause the clutch to stay engaged when the AC is off? Thanks for any help. My truck is a 2017 Ram 1500 Laramie with 5.7 Hemi.

 

[Bateman69]

If you have the air routed through the windshield defrost, it will kick on the AC to dry the air, regardless if the AC button is pushed or not.

 

[indept]

That happens to my truck every spring & fall. Sometimes I turn the AC on for a minute or so then turn off, sometimes it turns the compressor off sometimes it doesn't. ???? It doesn't seem to happen in the winter or summer

 

[Mahilly]

Resurrecting my original post, as I still have not solved my AC bug. Hoping someone else has had and solved this issue by now. Thanks for any help.

 

[1999 White C5 Coupe]

Resurrecting my original post, as I still have not solved my AC bug. Hoping someone else has had and solved this issue by now. Thanks for any help.

Some vehicle HVAC systems have a humidity sensor which will turn on the a/c compressor when the HVAC system is operating (independent of the a/c “on” switch or using the defroster mode).

If you’re in a high humidity area - that may cause the a/c compressor to operate frequently.

If the humidity sensor is defective, that may cause the a/c compressor to operate continuously.

 

[Mahilly]

Thanks, I will check this out. Appreciate the response!

 

[Mahilly]

Update: I pulled the humidity sensor and the problem still persists. So the next question: does the absence of a humidity sensor trigger the AC to stay on? Or does removing the sensor with no change rule out the sensor as the problem?

 

[TC]

I think you need to replace the sensor. You most likely have a P1009 code stored and will need to be cleared after new sensor install. I recommend using Mopar brand sensor as I tried a cheap Amazon one and it did not work. Went with OE and problem solved. I was not experiencing the compressor on like you but I wanted the code gone. I do live in a dry environment so maybe it makes a difference.