This 2003 GMC Envoy came in with the complaint that the a/c will only blow out the defrost and floor. Not through the dash vents. I checked codes and found a code B0263 for a fault with the mode actuator. I first ran into this problem after changing a battery in one of these vehicles last year. Whenever the battery is disconnected the HVAC unit will perform a recalibration of all doors. This causes the door motors to be moved full cycle and the mode door will stick some times. I now hook a jump box to the system before changing the battery in Trailblazers or Envoys to prevent a recalibration from occurring. This way I will not be blamed for a stuck actuator motor.
Anyways to change the actuator motor, first drop the hush panel under the driver’s side of the dash. There are some parts that have to be disconnected from the panel including the turn signal flasher assembly shown in the next picture.
Next, I removed the lower dash knee panel to have a little more room to work.
I had to pull a push pin retainer out at the left side of the duct work in order to remove the driver’s floor vent.
Now, I could finally see the actuator on the side of the heater a/c box.
I removed the actuator and installed the new one. Performed a recalibration with my Tech 2 and put all the panels back in place. A recalibration can be done by disconnecting the battery for at least one minute, reconnect the battery, start the engine and leave the a/c controls alone. I would recommend letting the engine run for at least two minutes, turn the ignition off for at least ten seconds but no more than thirty seconds and then restart the engine so that confirmation of the repair can be done.
I do not recommend connecting the wiring to the actuator until it is installed. They come prepositioned for easier installation.
The notch at the lower edge of the gear is an alignment point. There is a corresponding tab on the door linkage that needs to be lined up with this notch.
To purchase the mode valve actuator, please click here. To see updated information about actuator positions and alignment, please click here.
No it is not the same part. Yes I have worked on these before. What is the complaint with the a/c system on your Malibu? I will be away till Monday.
Is this the same part for a 2000 chevy malibu? It seems that my car dosent have one that i can see, rather it uses vaccum air tubes. Have you worked on this before?
They do work but not very well. The better way is to use a jump box. Connect the negative cable to a good engine ground. Connect the positive cable to the battery stud in the underhood fuse box. Make sure you turn on the jump box switch before disconnecting the battery. Keep in mind that the battery system will be hot and take care not to short the positive cable out.
Hi, what is the best way to keep power to the car while changing the battery? (in order to prevent the mode actuator problem). Do those 9V backups that hook up to the cigarette lighter work?
Ed said. I saved about $400 bucks by doing this myself Thanks to your directions and illustrations I was able to get it done. However, it will make installation much easier if you have a palm ratchet before you start. I had a hard time getting the screws out when removing the actuator. Putting them back on is no easier. And how do you align the white geared section with the pin when you can’t see them. I just did it by feel. Lucked Out! But I couldn’t have done this without the confidence you instilled. Total job with the correct tools should take about an hour.