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.
Assuming you installed anew actuator and that the clicking is coming from that actuator, more than likely the gears are not properly aligned. To be sure which actuator is actually clicking place your hand on all nearby actuators and feel which one is the culprit.
Hi Sparky,
I changed the mode actuator on my 2006 chevy trailblazer and now the dash vents work fine but it is making a clicking sound? Any ideas what it could be? Thanks!
It sounds like you have adjustable pedals in your vehicle. I have never done one of those, but from my understanding the gas pedal assembly needs to be removed to replace the mode actuator.
2004 GMC Envoy..It has the late mode U shaped vent tube..I really don’t see getting this thing out with out removing the whole dash..I can’t even reach up there with the rachet and get to actuator bolts to remove it..There is no room. I really don’t want to pay a deal 1K plus to fix this 40 dollar part. HELP!!!
Probably a 10 percent chance a recalibration will work but it is free and worth a shot.