This 2002 Chevrolet Trailblazer came in with a clicking sound under the driver’s side of the dash and erratic control of heat and a/c, hot and cold, air from the driver’s side of the dash. To find the actual site of the clicking noise, I had to remove some of the underside of the dash. Two screws up top.
Two screws under the bottom for the black hush panel.
Drop the hush panel down and unclip/ unbolt all of the stuff attached to it.
Remove the two screws at the lower edge of the knee panel. Lower and remove the knee panel.
Remove the four 10 mm nuts that hold the inner aluminum panel.
Remove the aluminum panel.
The driver floor vent duct needs to be removed. The left end of the duct has a retaining clip in it, that holds the duct in place. You have to either remove the clip or firmly pull down on the left side of the duct and wiggle it until it comes loose.
Remove the hold down screws for the actuator through the openings in and around the bracket, 5.5 mm.
Remove the two 10 mm nuts and the wiring harness clamp from the studs as shown below.
Remove the 10 mm bolt from the leading edge of the bracket.
Now go back and loosen the studs as shown. You will need a torx socket for this operation.
With the two studs loosened from the inner aluminum bracket, grab the sheet metal bracket and pull it towards the steering column. This will allow enough room for the actuator to come out.
The new actuator did not come in the same position as the old when it was removed. You can purchase a new actuator by clicking here.
The old actuator had a part number 16164972 and the new actuator has a label with part number 52402599.
I connected it to the wiring and turned the key on until it matched. I turned the key off as soon as it was in the correct position so that the actuator would not over travel and possibly get stuck.
I do not remember at this time if I left the wiring attached or disconnected it before reinstalling it in the dash. The sheet metal bracket has to be pulled again to get the actuator back into position. Then take your time and push the bracket back into place and align the two studs into the aluminum bracket, so that they will not cross thread.
That would indicate a potential problem with the mode actuator. However, when I listened to the sound on your video, it sounded much louder that any of the door actuators. The noise to me sounds like something stuck in the blower impeller blade, ABS motor or suspension compressor.
I have some more information on our clicking sound. Yesterday, when my wife hit the mode button on the AC to change the air flow from dash and feet to windshield and feet the sound started. It turned off when changing the mode to feet only.
Thank you for taking the time to listen to the video and give me your opinion.
I watched and listened to your video and no, that is not the sound of an actuator ticking. It sounds like a much larger motor turning with some interference. Possibly a blower motor, adjustable pedal motor or ABS motor. It could even be feedback in the speakers.
Is this the clicking sound that you were referring to?
Trying to figure out what this problem is with our vehicle.