2012 Tahoe Dual Climate Control- Blend doors

[Simpleman76]

I have been working on a 2012 Tahoe with dual climate control a couple times over the past year. I have worked on it on 3 or 4 different occasions for the same problem. i will lay out the situation for each time. I am looking for some input on where to go next in fixing the problem. The customer complaint is blowing hot air on drivers side and unable to change temp or select defrost. The first time I worked on the vehicle I replaced the blend door actuator for passenger side. I checked the blend door condition before installing the actuator and it felt fine. I installed the actuator and finally got the system to reset after trying every reset i could find. I drove the vehicle several miles and assumed it was fixed so called the owner to pick it up. Once owner picked up vehicle and got home it broke again. So next visit i ordered a new control panel, replaced the control panel and still no help. I removed all the actuator and disassembled each one and cleaned the inside of the old dielectric grease and ran each one with a 9v battery to ensure they were working. Reinstalled the actuators and got the system to reset and it worked for about 1 month. Owner reported same problem again, so I found a Tech II tool and calibrated the blend doors and scanned for faults the only fault shown was for the temp sensor in the headliner, so i replaced it. Reset the blend doors and everything worked for another month. I figured if it broke again I would replace all 3 blend door actuators, well it did break again and so I replaced all 3 blend door actuators reset the system and it has worked for another month. Today the owner has informed me that it has quit working again. Any ideas? 

 

[Mikebtte]

Sounds like one of the doors is possible getting hung up on something. Maybe this is causing the doors to loose calibration on occasion. Maybe you can get a telescoping camera in the duct work to monitor door operations.