I have an 07 350z roadster with around 55k miles. For the last few months, the a/c fan will not kick on automatically. Rarely it will, but other times it takes up to 20 mins. Any help? Thanks!

 

On my 2004 the plugs occasionally come loose from the controls. I think this problem was originally created when I swapped out my Bose stereo for a Kenwood.

Make sure the ribbon cables are plugged in tight.

 

A little late, but wanted to post the fix...

So the problem was in fact the blue a/c fan relay. I finally found it after removing the fuse panel by pedals. The relay is located behind the panel. It is not the easiest thing to remove, but possible. There are two (or three) relays.