Also back to your point about the CCU, there are actually 5 bulbs. There are 3 in the knobs and there are 2 more behind the panel.

It is best to get these from behind the panel because the plastic on the panel tends to disintegrate after 30 years and crumble. IE Don't undo the big nuts behind the knobs, or the whole thing will fall apart on you. Luckily I came across a NOS one on eBay.

The two upper bulbs can be reached while you have the auxiliary panel out. They are on the same string with the spider bulb (say it with me, spider bulb, spider bulb, does whatever that spider bulb does....) and can be pulled out from behind the panel.

Also just FYI if you need to change out the dial switches that can be done from behind as well. You just have to be a contortionist to get your hands back there but it is possible.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech