My 2012 Grand Cherokee has the manual dual zone HVAC system. I have two issues at this time. 1. The fan when set of full, will erratically speed up and slow down. 2. The passenger side is on full heat. I took the vehicle in for diagnosis. They told me that the fan resistor and the blend door actuator need replaced(identified by computer codes?). Their quote to do so, seemed very high to me. I changed the fan resistor. That did not fix the fan speed issue. One odd thing that happened is that the blend actuator started making a loud popping sound after we got it back from the shop (gears slipping?). I took the actuator off and adjusted the temp dial to see how it functioned. It ran then stopped and then would run again. Not sure if this is normal? Both gears have no damage. I opened the actuator up and all gears were also fine. I ran the car, set the temp control to full heat, manually set the blend door to full heat and reinstalled the actuator. Still does not work. Is HVAC control bad?
What makes this problem better or worse?
nothing
How long has your 2012 Jeep Grand Cherokee had this problem?
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No, I'd say that the HVAC control does not appear to be faulty. Your blend door actuator on the passenger side does appear to be faulty based on the description of the concern plus the noted popping noise. The actuator typically cannot handle a load of turning the door in the plenum as needed. Now, alternatively, the plenum doors could be binding or fractured. This would be less common but is still possible. I'd still replace the affected temperature blend door actuator if that was what was seen to be faulty. As far as the blower control, for manually controlled climate control systems, I don't know of any component in a manual system that can fluctuate the blower speed. It's manually set on multiple positions from low too high. Circuit testing may be necessary to see if the power remains the same to the bower as the fan varies speeds.
Thanks Dave. I checked the blend door movement and it moved freely by hand. I used a mirror to see inside the plenum (as good as I could) and did not see anything of concern. I will try replacing the actuator. I will check the voltage to the fan motor.
Thanks again, Mike
Thanks Dave. I checked the blend door movement and it moved freely by hand. I used a mirror to see inside the plenum (as good as I could) and did not see anything of concern. I will try replacing the actuator. I will check the voltage to the fan motor. Thanks again, Mike