This 2004 Chevrolet Trailblazer came in with the air flow stuck coming out of the defroster. I have already done a post on how to replace the faulty mode actuator, but I did not have a good enough picture to identify all of the actuators on the driver’s side of the dash. To see that post please click here. The view below shows the three actuators and is taken from the perspective of the driver’s feet, looking above the accelerator pedal and towards the center of the dash.
If you click on the picture it will enlarge to show more detail. This layout generally applies to 2003, 2004, 2005 2006, 2007, 2008 and 2009 Chevrolet Trailblazer and GMC Envoy. It also applies to Buick Rainier, Isuzu Ascender, Oldsmobile Bravada, Saab 9-7X and Chevy SSR. This second group of vehicles, of course did not exist, during all years between 2003-2009.
Once the mode actuator is removed and the new one is ready to be installed, you will need to locate the indexing pin as shown in the picture below. That pin slides into the notch on the white gear on the actuator.
I slide the new actuator into place with the notch and pin aligned and then rotate the actuator slightly to align the mounting holes.
The actuator on the right is the new actuator and the indexing slot is clearly marked. Please click on the picture to enlarge for a better view. The picture also shows the over traveled (stuck) position of the old actuator.
If you would like to purchase the Mode Valve Actuator (part # 15-73596), you can do so by clicking here.
The first time I did it, the a/c was off when I started the car … and nothing blew out of the vents after what I presumed to be a re-cal.
The second time I had the location control set to floor and the fan on its lowest setting prior to the re-cal … voila!!! Not sure if it matters that way, but it worked for me. The vents were spewing ice cubes at me!!! 🙂
THANKS VERY MUCH for your helpful site!!!!
I’ve gone through all of the steps, but it’s still not working.
The bottom of the indexing tab gear seems to be all of the way at the bottom (towards the floor). If I’m supposed to leave the gear on the actuator as-is when I receive it, will the re-cal pick up on where it is?
Also, when you say to leave the a/c controls alone, does it matter if it’s turned on or off, or where the vent control is set prior to the re-cal?
Thanks … I’m not giving up on this!!!
Either you looked at the wrong actuator or there is something else wrong. The correct actuator, related to a code B0263, will have the white gear attached to it as shown in the pictures.
I just took mine apart and the actuator is turning, but won’t open the airway to the front vents. Is this normal when they stop working or could there be another issue why the vent does not open for the front airducts?
Thanks a lot great pictures excellent description Thanks Mike