Broken Rear A/C knob

[325iExecutive]

Hi,

I have a 2008 CX9. And I have noob question - My daughter broke the knob off from the rear a/c unit and now the rear a/c does not work. Would I need to replace the whole rear A/C control unit? I tried to find out pricing from online retailers and was successful.

Any help is much appreciated...

Thanks