My '83 K100 has had the frame off for powder coating and is mostly going back together ok. But now the turn indicators (blinkers) which were working fine previously have now 'gone weird'. Left front and right rear aren't working. Bulbs ok, earth checked, switches turn on and off properly. The rear worked with the hazard light switch and then with the right bar switch but has now stopped again. Disconnecting the hazard circuit has no effect. Where do I go next?