Dash lights out on '87 w126
 

Last night on my way home from work all of my interior lights went out (dash and center console). I checked fuses, however everything else works, I'm pretty certain that which ever fuse covers those lights is most likely covering some other function as well.
My best guess is the potentiometer on the instrument cluster is toast. I have never really used it (does anybody constantly adjust the brightness level), except to reset the trip odometer.
Is there any way for me to confirm that I am correct before pulling the instrument cluster?

Thanks in advance!
justin

Oh...the car:
1987 560SEL
Well Loved