Paul.....on the clicking....
It means that $5.00 diverter motor needs fixed/replaced yet it is a full day job to get to it.
It is located on the far right side of the ac air box. It looks quite like the 2 motors near the drivers right foot.
To get to the recirculating air diverter motor, one must remove the top dash pad, and pass air bag and, and, and.....
Just to get to the 2 screws and one connector.
By the way,
have you checked the cabin air filter just below the glove box?
There you will see the diverter and can get an idea where the motor is located. Again its a $5.00 part but a $500.00 job.....on a good day.
Coby7 has a fix....he just disables it
On your keyfob...it would still be worth it to speak with Coby7 and have him service it because he can quickly tell if it is x-mitting and while there, spiff it up.
The 2 connectors on the Body Control Module (BCM) are located, inside, pass side, right foot kick panel. There is the inside cabin fuse box..(The BCM)
A quick google search will show image of the Cobalt BCM, location, and how to...
Image found using search engine duck duck go using search terms Cobalt BCM Location and found here on your cobalt and it's a Coby7 image too!