The C250 has been a problem posted here several times.As you can see in the video the fuse is well hidden , The reed switch is another part that fails plus as you see on flush button the micro switch in the board can be a problem to

ur van is now 13 years old and its first 10years we had replace the bord housing the flush button. If you are worried about the casette full light not working then there is an easy fix.Get your service engineer or yourself and fit a small toggle switch to the printed circuit board and pick up the live wire from the loom and connect to switch.The cost will be cheaper than having to replace board. I hope this helps.