1989 BMW 3 Series dash electrics

I had a major illumination problem with my 530d. For a while my radio was on but did not illuminate, volume would not adjust, indicators not flashing but worked externally, no main beam illumination on dash, heated seats inop, air con inop, fog light illumination inop, the list went on. Eventually I sat in the driveway one day and put on ignition then pressed the lock/unlock button on key fob (while ignition on) and eventually got everything working again, it was almost like I reprogrammed everything to work again. Like it had lost it's memory on what worked. It had the BMW tech's scratching their heads. They kept blaming the K-Bus line which operates everything. My speedo etc worked ok. Try messing about with the lock/unlock and see what happens. Mine never cured overnight, it took a few weeks of messing about but I got there. Ian