Original Author : LesabreUltra
Thought I'd bring my write-up over from the other forum to help future members.
This guide will show you how to diagnose and remove a faulty airmix actuator, as well as describe a quick temporary fix and explain the installation procedure.
The removal and installation will apply to any 1992-1999 LeSabre with automatic climate control (also known as ECC - electronic climate control). The guide should still be helpful to anyone with an ECC however, regardless of whether or not your car is a LeSabre. The orientation, part numbers, functionality, and directionality of the actuator and ECC is the same for all 92-99 H Bodies, however different models will have the ECC at varying locations behind the passenger's side glovebox and may be harder to see or get to than the example in this demonstration.
If the temperature display on your ECC is blinking, then it means the system has recorded a malfunction. 9 out of 10 times, it's due to the airmix actuator breaking. If you were to open up a faulty airmix actuator, this is what you would see:
The cracked gear is the source of the problem.
The plastic gear is subjected to a lot of pressure (it has an extremely tight fit with the central rod arm) and over time it will break. Sometimes it can be prevented, or at least delayed. If you ever disconnect your battery, make sure you turn the ECC OFF before doing so. If you don't, the next time the car is started the ECC will run the actuator through it's full range of motion to check calibration which subjects the gear to added stress.
The symptoms of a failed actuator include the inability to adjust the air temperature, noisy operation (sounds like a drawn out creaking behind your dash), or inconsistent air temperature. In the case of dual climate control equipped vehicles, one side may blow cold air while the other blows hot, with the inability to change the temperature on either side. In many cases, the ECC registers a failed actuator before the gear is cracked badly enough to prevent temperature changes.
There are a couple of ways you can check to see if your blinking ECC is caused by the airmix actuator. The surest way is to take it to a dealer with a Tech II scanning device and pay them to diagnose your system. The cheaper do-it-at-home way is as follows:
First, open your glovebox and pull loose the stopper tabs. This is simple and easy to do, just pull forward and they will come loose. The result is this:
Next, take a peek inside and you will see your airmix actuator (circled in red).
In the above picture, my actuator has been disconnected from the airmix door arm (circled in blue)...that rod sticking out is the airmix actuator arm. Yours will still be connected.
Start the car and turn the temperature to full cold. Depending on the outside temperature, the actuator may or may not move. Wait a second to watch the movement. With the temperature set on full cold, the airmix actuator arm and airmix door arm should either move or remain all the way to the left, as follows:
Next, set the temperature to full hot on the climate control. The arm should definitely be in motion at this point. It should move all the way to the right, as follows (minus my finger):
Watch the arm for a smooth, continuous, and quiet motion. If the arm does not move, makes excessive noise, or if it doesn't move smoothly, then your actuator has failed.
Another way to test is to try to move the actuator arm by hand (don't force it!) If you can turn it easily then the main gear inside is cracked. It should not turn at all.
I ordered my actuator off of RockAuto.com. You can also pick one up at GMPARTSDIRECT or at your local dealer. There are two available, and to know which one you need you will need to check your RPO codes. The RPO codes are located on the plastic lid of your spare tire on a square label. Pull the trunk carpet up and you should see the label with many three digit codes on it. The codes to look for are C67 and CJ2. If you have C67, you will need to order AC Delco part number 1571835. If your RPO label has CJ2 (such as mine did), you will need AC Delco part number 1571923.
Those of us with LeSabres have it relatively easy compared to Bonnevilles as far as removing and installing the actuator. You will need a 7/32 inch socket and a ratchet to remove the two bolts holding the actuator in place. Don't forget to disconnect the actuator arm. Here is what you will see (the actuator is circled):
You should be able to find and remove the bolt in the front without much difficulty. However, the bolt in the rear you will have to find by feel and will be a bit more difficult to remove. Be prepared to potentially lose the tool you used to remove the bolt with as space is tight. I tied fishing line around my socket to keep from losing it both when I removed it and when I installed it. BE VERY CAREFUL NOT TO LOSE THE BOLT!
Once both bolts are removed you can then pull the actuator. Be sure to disconnect the electrical connector. Remove the actuator arm (the metal half of the arm on the actuator, circled):
As you will need it to put on the new actuator. It doesn't come with the bolts or the metal arm. Be sure to note the orientation of the arm on the old actuator before you remove it.
If you are waiting on your new actuator to arrive, you can temporarily alleviate your situation by tying off the airmix door arm (the part you see circled)...:
...to the left for cold, or to the right for hot. The airmix door is pulled by vacuum and will automatically revert to full hot (to the right) if allowed to wander freely. You will not be able to adjust the air temperature with the ECC while it is like this, and it will continue to blink. But you will have whichever temperature of air you most prefer and you will be able to adjust fan speed and direction, as well as A/C compressor function.
When your new actuator arrives, collect the two bolts and the actuator arm. Put the arm on in exactly the same orientation as it was on the old actuator.
Next get ready to install the actuator. Again, I tied fishing line around the socket I used and also around the bolt to make sure I didn't lose either. I was glad I did, because I dropped both.
Attach the front bolt and the electrical connector first, they're easy to get to and will make it easier to attach the rear bolt. After that, the rear bolt will take time...try to tighten it down there by hand at first, then turn it with the socket, and when you have enough clearance, the ratchet can be used to tighten it the rest of the way. Cut the lines off the bolt (if you did that) once it's tight.
After it's in, it's time for calibration. Start by turning the temp to the maximum heat setting.
Wait until the actuator arm moves all the way to the right. Move the airmix door all the way to the right, hold it there, and then snap down the metal connecting rod to connect the actuator arm and airmix door arm.
Next turn the temperature to the maximum cool setting.
Watch the action of the actuator arm, connecting rod, and airmix door arm as a whole for smooth, quiet motion throughout the full range. Verify that the airmix door moves all the way to the left.
Then set your temperature to the desired setting. Turn off the ignition and restart the car. Either let it idle for a few minutes or take it for a test drive to verify that the ECC has stopped blinking. If it has, then you are set to enjoy air at the correct temperature again!
Hope this will help someone enjoy their drive with a little more comfort.