Need to know how to wire up the directional signal relocation kit (kit number 68412-99). The wires on my 1990 Fat Boy are both black, one has a copper core and the other has a silver core.

The signal lights in the kit have purple, blue and black wire. If I hook up the black and purple wire, no matter what I do, I can't get them to work properly - they come on but don't flash - the rear directional signals don't work at all. I've tried every combination but I just can't seem to get it....

I would appreciate any assistance that you can provide

 

Newer bikes have a three wire setup for the front turn signals/running lights with the Black wire as the ground line.
I'm not sure about earlier bikes but if yours had running lights then the original light fixture must have used a frame ground instead of a wire and you need to ground that Black line to the frame. Then you can use the Blue for the running light and the Purple (Violet in the book) for the turn signal.
To double check that the Black wire is the ground use a volt/ohm meter set to measure ohm's to see if there is a circuit between the side of the bulb socket and the black wire. It should show 0 ohm's resistance between the two, if not leave the one probe on the side of the socket and use the other to check the Blue and Purple lines. One of them should show 0 ohms. Which ever one it is "IS" the ground line and the other two are for the running light and turn light.

Next take the meter reset to measure voltage and put it between one of the black wires on the bike and the frame (and bare metal on the engine works fine). Turn the bike on and see if there is 12V, if not check the other one. One of them should have voltage on it with the ignition in the "ON" (turn the headlight on if it doesn't come on with the ignition switch) position if your bike originally had running lights. Whichever line has it should go to the Blue line running light element.
Then try to turn on the turn signals and see if the other line has 12V. At this point it might not work because you may have accidentally popped the fuse when you hooked the ground line to it. If you don't have power check the fuse first.
If you find power on the other with the turn signal activated hook the Purple to it. The signals should work normally then.
If that doesn't work I think your going to have to get hold of a set of wiring diagrams (in the back of the factory service manual) to see which wire goes where.
If your lucky you might be able to find another brand of service manual with the wiring diagrams in the reference section of your local library. For a small fee they will often make or let you make photocopy's of the pages you need.
Good Luck and let us know how you make out.

 

Thank you for your help, I was finally able to figure this one out on my own. The black wire was the ground wire. Also thank you to Buddy7394 for their message with assistance.

 

Damn, all that typing wasted.
Glad you got it straightened out.

 

the typing wasn't wasted - hopefully it will help someone else one day ...