It just provides an un-intrusive or non-distracting light at night time, so you can see some of your things around the dash area. Next time you're in your PM at night, put your hand near your climate controls, you should notice that your hand is slightly illuminated. I believe it comes on automatically when you turn your headlights on, then it's just on.
Thanks. It comes on when the ignition is on. I will look tonight to check it out. It must be for when you have headlights out as if they are on the dash controls would light up. Of course the map/reading light are right there to use so this must be for some stealthy actions. :^)
LOL, I think it's there to provide a little bit of light while driving so you can see something like if you were reaching for your beverage or something. I'm going to be going somewhere shortly and will see if it is on all the time regardless of headlights on or off.