Subaru Repair: Odometer Cryptic Message, odometer reading, illumination level

Question
I have begun noticing that "ILL.5" or ILL.6" is occasionally replacing the numbers
on my 4-cylinder '05 Outback odometer (which is currently about 30,000 miles).  
It appears only for a brief moment and does not seem to be influenced by my
driving up a steep grade or coasting down.  There also does not seem to be any
evidence of the engine performance being challenged.  Would you be able to tell
me what this cryptic message means?  Thank you for your time!

Answer
When I would drive an Outback I would notice the same thing and I thought there was some kind of defect with the instrument cluster and the ILL.5 or ILL.6 was a failure code. I was wrong! You are seeing the instrument panel illumination level displayed. The lowest level of instrument panel lighting is ILL.1 and the brightest is ILL.6. When you turn the control, which is to the left of the Left Right mirror control button, ILL and a number from 1-6 should show above your odometer reading. And, from what the owners manual states, this will not work if your headlights are off, unless you have a turbo.

Zeke