The Gear May Be Stripped
Sometimes the gear within the actuator motor of the air door becomes stripped. The opening air door will then bring fresh air in from outside. When drivers set the heat function, max A/C or defroster, the door will close, recirculating air which is already present inside the vehicle. This results in damage to the nylon gear teeth within the motor.
Each time the vehicle is shut down, the air door will open automatically. When the vehicle starts, it will try to adjust automatically based on whatever command position is selected within the A/C system control panel. Unfortunately, once the gears are stripped the door won’t be able to reach the proper position.
It should be emphasized that General Motors has had a number of issues with the actuator motors on different models. Aside from the Chevy Cobalt, drivers have also reported issues with the Chevrolet Cavalier manufactured between 2003 and 2004.
How The Motor Works
The Chevy Cobalt motor is able to sense the moment the door traverses to the stopped location. As a consequence, it will attempt to close this door all the way if no resistance is felt. This is the reason why drivers hear the clicking sound. And they will continue hearing it each time they start up the vehicle. In order to resolve the issue, the actuator motor of the air door will have to be replaced.
Those who attempt such a replacement DIY will have their hands full however, as the part is deeply buried within the vehicle and requires the dashboard to be disassembled. Those who review the official Chevrolet manual will note that the entire dash assembly has to be removed. The good news is that the replacement part itself won’t be expensive, so most of the cost will involve labor.
How To Stop The Clicking Noise Without Disassembling The Dashboard
A workaround has been discovered, which allows you to resolve the clicking noises without needing to disassemble the dashboard. The gear teeth are subjected to a great deal of stress while holding the door shut until motor deactivation. As such, the best way to resolve the problem without having to replace the door actuator itself is to alter the flap’s closed position.
To do this, you would use a couple of wire ties to prevent the door returning to its initial position. Since the motor won’t reach the gear area which is stripped, the clicking sound will stop. However, it should be emphasized that this is a temporary fix. How long it will last depends on the actuator age and the frequency with which it is used. Videos have been published on various websites showing step by step instructions on how to use the wire ties.