Sno White

The radio in the HHR is never off – entirely. It supplies the sound for the buzzers and alert tones, turn signals, etc.

Does not sound like relays – there are some relays in the BCM.

Ventilation door mis-activation would be my guess, but I do not know just what actives the ventilation doors on the HHR. If they are electric or vacuum operated?

If I understand your statement about the camera and clock display on the radio head – the sampling of the camera is so fast it only shows a partial multiplexed display of the clock.

My bet is you will soon notice something else not working on the vehicle that will give a better indication of just what is wrong.

ChevroletCustomerService

I advice that you take your vehicle into a dealership just so you don't end up having future concerns.

Jessica L.
Chevrolet Customer Care

Lucky

I worked for Chrysler as a tech for many years and I have heard that type of noise many times. We had lots of problems with our mode and temp door actuators. They were electric motors with plastic gears and would make that type of noise at the end of its travel. After some time and a lot of replacements they came out with a reflash to the body computer to stop the motors from traveling so far.

mikiec

Thanks,

I'll check with the dealer.

Mike

bsstan

I have the same or similar problem. When I first start my car, I have a knocking noise. It is like a door, trying to shut under the dash. The sound is similar to one my pinto made when I would go from heat to defrost. Manually switching.

Oldblue

That would be the vent door actuator motor is shot!

Check here

https://www.chevyhhr.net/forums/prob...ctuator-51029/

Kyle Smith

mine does the same thing, but I hit the inside air recirculater and it stops

Oldblue

Same as I wrote in August 2016, blend door actuator motor is starting to fail.