light not working on heat control

[DevilGirl]

I tried searching for an answer to this question, but could not find one (unless I'm using the wrong search terms...).

Just recently I noticed that one of my heat control knobs no longer lights up. I have a 2009 hatchback, so my control knobs are vertical. It's the bottom one that controls the temp setting.

Any idea on how to fix this so it lights up again? It wouldn't be such a problem other than the fact that when I drive to and from work, it's always dark out (4:30am leave home, and back in my car for the drive home anywhere between 5:30pm and 7:00pm).