How To Fix Climate Control Knob

We had only lukewarm heat in our 2012 LT sedan and I suspected knob issues since I could not hear the cold air door closing all the way when you moved the knob to the hottest setting. It also felt kind of weird toward the end of the rotation.

Temp was almost 40 today, so I took it apart. I did not have any special tools, but you can pull the upper bezel by carefully using a small screwdriver under the "ears" at the top. I also used some odd plastic wiper adapters as shims to hold the loosened part away from the dash while working on the other side. No issues.

For automatics, you next need to remove the silver bezel from around the gear shifter (this is where the PRNDM lights up.) This is removed by gently prying out the small rectangular plug on the front right corner that appears to do nothing, then prying up from the rear. Pops right out, then you can unplug the wiring connector.

For the next step you need the gear shift in N. I started the car and put the e-brake on, shifted it to N, then shut down the engine. The lower plastic bezel around the shift console (which covers the two lower bolts for the HVAC controls) pulls out from the rear with four spring tabs, no screws or bolts.

Now the easy part... Four 7 mm screws and the control panel is out.

I did not have much play in the cables, so I had very little room to work. I disconnected the three electrical connectors to give a bit more space, but that did not change much.

The hardest part was releasing the lower white tab where the knob connects to the cable assembly. It is hard to get to the tab on the lower driver's side, even after disconnecting the passenger side mode door cables.

Once I got it apart, the cables were NOT out of the grooves... The "splines" inside the plastic assembly looked good, but I could not see around to the splines on the knob, since I did not remove it completely.

I started the engine and manually operated the cable assembly - it has a plastic pin on it you can turn. I heard the cold air door fully close several times. I spray lubed the assembly, then calibrated the knob and cable both to full-hot. I shut off the engine and re-installed everything.

Perhaps the splines in the knob are the true culprit in my case, still not sure, but I know how to replace the entire assembly should I choose to do that in spring. It is also possible that the cable assembly had a longitudinal twist in it that was causing it to bind and I somehow fixed this when I dis-assembled and re-assembled it.

It does have good heat now, and I told my wife we probably don't want to be turning the knob too much before spring... just use the fan speed and mode selector.

I was also having a pesky rattle at certain engine rpms in the tubes that go to the heater core. I could not get rid of this rattle after replacing the O-rings at the firewall connections. While the dash was apart, I removed the kick panels (the driver has one plastic rivet, all else is velcro and snap springs) and found the two tubes hitting against each other on the inside of the firewall. Actually, they are much easier to access from the inside than I thought. I stuffed a clean shop rag in there and no more rattle. Not as intended, I'm sure, but this car is 7 years old with almost 90k miles...

Test drive - all is good. Less than 1 hour and two problems solved. Not bad Thanks for the help on the forum!