Sonata 2010 heater system clicks
 

We love our new 2010 Sonata. But whenever we turn on the heater or the ac, clicking noises come from behind the dashboard, both sides, for a minute or less. I tested by switching back and forth between ac and heating; each time I switch, the clicking starts. It also clicks a lot more with road bumps. I suspect the tubes in the heating / cooling system are expanding and contracting. Any one else ever notice this odd problem?