As it happens, I took my instrument panel out yesterday too.

I took pictures of the connections before I undid them in case I couldn't figure it out.

I'd say it does fit somewhere back there. It may not be clear to you exactly where, but I'm almost 100% sure there's a spot. It's different than mine, so I can't help, but here's a couple of suggestions.

Do you have a trusted Mercedes mechanic you can ask?

How about the parts counter of your local Benz dealer? They have drawings on computer to identify the bulbs.

Do you have a local Benz parts yard? Those guys usually have some answers, although not always correct?

When does the light come on? During start up? Here's your chance to be a detective.

Good luck.

__________________
MB 1986 190D in my past
MB 1987 300E on the street
MB 1994 'Smoke Silver' E420 in my driveway
1999 Mazda Miata in the fun stable
1964 E-Type Jaguar Coupe- Sold
1970 E-Type Jaguar Coupe- Sold
1968 Corvair Monza Conv. with Turbo Transplant- Sold
1986 Merkur Xr4ti- abandoned
various mundane American autos

If I'd known then what I know now...

Hell, I'd probably still have done it anyways.