I have the same problem. All 4 of my door locks stopped working and the dashboard is cracked. This is a 2008 with less than 100K miles. Even under warranty the dealer would not replace them. Cost for repair - negotiated to $990.
I am so frustrated with Chevy right now I could spit. I just paid $1800 for a check engine light repair on a bulletin known problem - rough idle, oil consumption.. Results if you don't know and fail to take it in right way - need to replace #7 piston and ring. Just like it is known that the dashboards crack, and the door locks, quit, there is a problem with the valve cover assembly allowing oil to bypass the ring. And GM will not honor a repair.
I still have other minor repairs that are needed - another $600. This is turning into one very expensive avalanche. GM - are you hearing all of this from everyone?
Tried to get help from GM on cracked dash no luck I have also had problems with the door locks Inside door handles chrome coming off, oil consumption, outside door handles braking and valve covers stopped up even after changing oil every 3000 miles I also brought another one in 2012 I believe I am going to change brands After spending 144,000.00 on GM vehicles in the last 7 years