My next step will be to rebuild the front signal harness connectors (61132359999) and rear tail bulb holder harness connectors (https://www.fcpeuro.com/products/bmw...6tailrepairkit) and replace the rear bulb holders. I think (hope...) this will solve it because one of the bulbs in the passenger rear corner will not stay lit (flickers on and off) even though the harness connector is fully seated and the bulb has good contact with the seat. This was also the corner I performed the ground wire fix on.