I have a 2013 Harley Davidson Fatboy I'm changing the stock turn signals to aftermarket on the rea which wire is the hot wire the purple one or the black one.

SOURCE: turn signal wiring

http://images.google.com/imgres?imgurl=http://mysite.freeserve.com/hhog/diagrams/23_1975_FL_FLH.gif&imgrefurl=http://www.harleyhog.co.uk/wiringvarious.htm&h=2133&w=1310&sz=82&hl=en&start=4&um=1&usg=__7Mf2_b-KebTuaZcBpkMmz7bDKKU=&tbnid=4oYjK1wkFbSJPM:&tbnh=150&tbnw=92&prev=/images%3Fq%3D1978%2Bharley%2Bflh%2Bwiring%2Bdiagram%26um%3D1%26hl%3Den%26sa%3DX

Try the above link, good luck.

SOURCE: 2008 Yamaha YZF-R6 turn signal wiring harnes

sorry.. i don't know off the top of my head but super simple way to check.. get an electrical tester that pierces the wire and turns on a light.. ($5 at walmart--seriously) turn on left signal, check the wires.. the one that is flashing is your left signal... so on and so forth..

(this tool will be super handy in the future also)

:)

SOURCE: picture wiring diagram for 2003 harley fatboy

May I suggest a trip to your local library. Cycle repair books should be in 646 stacks of reference.
Otherwise you can Google for 2003 Clymer Service manuals on the internet.
I think Clymer had electrical diagrams in their books. I doubt that any except the HD service book would have anything about the physical location of the harness, but the pictures in the other books would help you.

SOURCE: engine diagram for 88 cubic inch harley davidson

I was able to pull up the complete maintainence book with wiring diagram, parts assembly, torque specs and part numbers by just going to www.1972 flh 80 harley davidson oem.com

SOURCE: 1974 Harley Davidson SPORTSTER TURN SIGNAL WIRING

I can help you with the wiring diagram but it will be the complete diagram. I have never seen just a turn signal only type wiring diagram. But, there's nothing to a '74 model Ironhead turn signal system.

All the wires for the system were gray but had these little "colored rubber bands" on the ends of the wires near the signal lights. The violet bands were for the left side and the brown bands were for the right side turn signals

Now, I cannot send the wiring diagram through this forum as it will not allow for an attachment. If you will contact me directly, I'll send you a wiring diagram as a jpeg attachment via e-mail. My address is [email protected].

Good luck
Steve