One indicator bulb in the instrument housing was not lighting. I pulled the instrument cluster out and tested the bulb which was good. However the foil trace that goes on the tab inside the hole in the circuit board the bulb holder plugs into had broken.
I used some copper foil to make a repair and I documented how I did it here.
The same technique can be used to repair any of these boards when a cracked or broken foil trace causes intermittent or complete bulb failure bulb. But sometimes the circuit board is broken, badly corroded and it isn’t salvageable.
BMW no longer sells the circuit board but you can find used ones for sale on eBay and some are in good condition. However someone took the time and effort to design a replacement light housing and circuit board that uses LED lights instead of the original incandescent bulbs. For a badly damaged circuit board where the simple fix I made is insufficient, these replacement boards will likely do the trick. I’ve not had occasion to install one of these, but you will find information about them here: