Ok so i just puchased a used 2004 mdx. There is a built in nav woth nothing but check disc on the screen. There is no disc in the drive. So my questions are as follows #1 am i required to have access to my nav system to operate the a/c? and #2 is it possible to find the 2004 version (original not burned) just so i can run my a/c if its needed?