Automotive Air Conditioning Information Forum

Hi all, This problem just started a couple weeks ago. If I run the fan with the AC off (for just outside air) the AC will be on and blowing cold even though the AC button is turned off. I checked under the hood and see the compressor clutch just stays engaged when the fan is on, even if the AC button is off. I have cycled on/off all of the various options for a/c, max a/c, defrost, 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 car is a 2017 Ram 1500 Truck with 5.7L Hemi.

Condition

Possible Causes

Correction

Constant A/C compressor engagement and warm air from passenger vents

1. Low refrigerant system charge

1. See Refrigerant System Leaks in this group (Refer to 24 - Heating and Air Conditioning/Plumbing/Diagnosis and Testing) . Test the refrigerant system for leaks. Repair, evacuate and charge the refrigerant system as required.

Tim thanks for your response, however my issue is different than the condition and fix you described. My issue is the compressor clutch stays engaged and blows COLD air when the AC button is turned off (and the fan is on). I can’t get the system to vent unconditioned outside air with the fan on (and AC button off). Thanks for any additional help.

Best to use a scan tool and check for trouble codes. Get a wiring diagram and trace power routes.

Hi, yes I have a scanner but no trouble codes are coming up. Also checked the refrigerant pressure and it’s within specs. I’ll keep searching for a solution. Thanks.

I would look closely at the defroster circuit. Most cars have the AC on while in defrost mode...this may be related