Instrument Cluster Troubleshooting

1990 325ic (cabriolet). The left turn signal indicator in instrument cluster does not light up. I have replaced the bulb, even switched bulb out with the right side indicator which does work. The turn signals work, and the flasher clicks, but the indicator stays dark. Where do I start to troubleshoot, do I pull the back off of the cluster and re-flow the solder to the bulb socket?

I use to have a friend who traced down these types of problems. He has not been seen for several years...
What is the cheapest thing you could do?
Maybe check the socket, and start from there following the solder lines.
Time, lots of time can be invested in a project like that and the fix could be as simple as a crack in a solder line or something like that. I am getting old and blind so I have one of those visors with high power glasses attached just to pull splinters. Something like that might be helpful.
Do you really need a turn signal light?
Best of Luck to ya.

Thanks for the response. I am getting adept at pulling the cluster so I am going to reflow the solder to the bulb socket. I live in a state that has annual safety inspections and the indicator lights are part of the inspection (no matter that the lights all work). I failed one inspoection for no horn and I asked the inspector if he had the ignition on for the horn test, reply "no, why" my response was it is a BMW,no power no horn. I asked him tos stand in front of the car and I turned ignition on, and blew the horn, he was not amused (no sense of humor). However I did pass the inspection.