My F2 had the rear fender chopped before I bought it. It was a crappy job and whoever did it installed a set of mini turn signals. The holes were drilled through what was left of the plastic really close to the edge. The left one broke completely. I decided to build some brackets and attach the lights using the license plate bolts. When I tried them out all four lightsflashed no matter which switch I hit. I surmised that it must be a 'common ground' problem. so I found some more plastic to drill and re-mounted them with no common mounting ground and viola! everything works as it should. The only bummer is wherethey are mounted, they poke out at a 45 degree angle from under the rear tail fairings just above the tire. Doesn't look too bad and since we don't legally have to have turn signals in my state it's all good.
So,,,,,, did anybody else know this????

 

It shouldnt be a common ground sense the left and right turnsignal wires are different. I was just adding the integrated taillight and did not have any problems with them. The only ground wires are the solid green which is a 1 into 3 wire so maybe you had something going on with that?