Ticking noise from dash

could be an hvac damper trying to open or close, or sometimes it is the 3 way coolant valve.

 

yeah mine does that too just turn the stereo up.

cant remember what it is but AC not affected its a damper door like Bisco says.

 

Here's what's happening.

The motors that move the dampers around have position sensors built in. As the sensors age, the position signal they send starts jumping around because the electrical contact is poor. The computer wants to keep the damper in a certain position, so when it sees the position signal jump around (even though it is just electrical noise and the damper didn't really move), the computer drives the motor in the other direction to try to make the damper stay put.

Of course that really does move the damper, and the position signal changes again, and the computer drives the motor back the other way.

There is a coolant control valve that works the exact same way, has a motor and a position sensor, and it can start doing the exact same thing. But the HVAC dampers are inside the dash in your ductwork, and the coolant valve is out in the engine bay, so it's usually not impossible to tell which is which. Not to mention you can stick your head under the dash and see the damper servo jumping around.

Some of the damper motors (there are three) are easier to get to than others. The fix is super simple, so the only difficulty is if the one doing is one of the tough-to-reach ones. yitznewton found a very flat offset screwdriver to be helpful.