sounds like the blend door motor.

 

I have a 2021 that's going into the dealer tomorrow. It's blowing air out of the dash vents, floor vents and defrost. When I change the settings on the screen, nothing changes. I'm thinking blend door or the whole distribution housing.

 

I'm not sure it is the blend door - when they get stuck (broken actuator gear, etc.) it effects temp control, but not where the air comes from. I think there is a different actuator that controls that. I'll have to take a look at the FSM, I was poking through it last month when I replaced the blend door gear - air flow direction/volume changed, but temp stayed constant on the passenger side.

 

This is what is happening to my ‘13 SXT. Would you mind breaking down the solution a bit simpler for me, please? A/C works fine. It is just only blowing cold on passenger side. Outside or engine air every other vent. Just the opposite when I use the heat. I could hear a clicking sound when I changed from defrost to “face” vents for a short time before it completely stopped working driver side and armrest rear. Side note: third row ceiling vents haven’t blown temp controlled air since ownership.

 

From the FSM, there is a Mode Door actuator that controls where air is routed. This is independent of the blend door actuator, with controls temp:

The two mode door actuators are connected to the A/C-heater control through the vehicle electrical system by dedicated two-wire leads and connectors of the HVAC wire harness. The mode door actuators can move the panel/defrost/demist/floor air doors in two directions. When the A/C-heater control pulls the voltage on one side of the motor connection high and the other connection low, the mode-air doors will move in one direction. When the A/C-heater control reverses the polarity of the voltage to the motor, the mode-air doors moves in the opposite direction.

When the A/C-heater control makes the voltage to both connections high or both connections low, the mode-air door stops and will not move. The A/C-heater control uses a pulse-count positioning system to monitor the operation and relative position of the mode door actuators and the mode-air doors. The A/C-heater control learns the mode-air doors stop positions during the calibration procedure and will store a diagnostic trouble code (DTC) for any problems it detects in the mode door actuator circuits.

The mode door actuators are diagnosed using a scan tool. The mode door actuators cannot be adjusted or repaired and must be replaced if inoperative or damaged.

It is the same type of actuator that is used for blend door control:

The mode door actuator (1) is a reversible, 12 volt direct current (DC), servo motor. The mode door actuator is located on the upper right side of the HVAC air distribution housing and mechanically connected to the mode-air doors.

The mode door actuator is interchangeable with the actuators for the blend-air doors and the recirculation-air door. Each actuator is contained within an identical black molded plastic housing with an integral wire connector receptacle (2). Each actuator has an identical output shaft with splines (3) that connect it to its door linkage and three integral mounting tabs (4) that allow the actuator to be secured to the air distribution housing. The mode door actuator requires mechanical indexing to the mode-air door linkage and is electronically calibrated by the A/C-heater control.

 

Thank you Moose135! Sounds like the mode door actuator is my problem. From what I see I would have to remove the dash to get to it. Well beyond my abilities.

 

It doesn't sound like a big job, but it may be tricky to get to. Replacing the gear on the passenger side blend door actuator was easy, it just took me a little bit to get the dash parts (glove box and surround) off to access it.

Disable the airbag system before attempting any steering wheel, steering column or instrument panel component diagnosis or service. Disconnect and isolate the negative battery (ground) cable, then wait two minutes for the airbag system capacitor to discharge before performing further diagnosis or service. This is the only sure way to disable the airbag system. Failure to follow these instructions may result in accidental airbag deployment and possible serious or fatal injury.​

Disconnect and isolate the negative battery cable.

1. Remove the right side instrument panel silencer.
2. Remove the right side floor distribution duct from the HVAC air distribution housing (Refer to 24 - Heating and Air Conditioning/Distribution/DUCT, Floor Distribution - Removal) .
3. Remove the three screws (3) that secure the mode door actuator (2) to the mode door bracket (4) located on the right side of the air distribution housing.
4. Remove the mode door actuator from the air distribution housing.
5. Disconnect the wire harness connector (1) from the mode door actuator and remove the actuator from the vehicle.

When I did the blend door gear, they recommended removing the distribution duct (step 2 above) as well, but I couldn't figure out how to get it disconnected at the top. I was able to move it a little and squeeze past it, but it probably would have been easier with it out of the way entirely.