I have an 07 Sportster.

Has anyone used a 5 pin to 4 pin trailer harness to make a low cost run, brake, turn signal system?

How did you resolve the issue of having a front brake and a rear brake wire coming from the bikes stock harness?

Or, can the 2 wires be connected to the trailer harness's (to vehicle) single brake wire?

My guess is something needs to be on the front brake and rear brake wires prior to connecting them to the trailer harness's (to vehicle) brake wire.

The wiring diagram for my bike says.....

Black - Ground

Violet - Left turn

Red/Yellow - Brake light

Blue - Tail light (running)

Brown - Right turn

Orange/White - Accessory

If this is correct, please, let me know.

If anyone has used a trailer harness to do this, please chime in, this sh@t is driving me nuts! LMFAO

Thank you in advance for any and all your input.

 

Turns out a 5pin to 4pin trailer harness works like a charm.

 

Good work, I figure the two brake wires can be put together, no power till the switch on either is hit, they must not interfere with each other anyway, cause you hit both brakes most the time.

John

 

The wiring from the bikes harness I labeled at the beginning of this thread is good.

My assumption is the front and rear brakes wires go through a diode prior to reaching the harness that goes to the rear.

If you eliminate the orange/white (accessory) wire by cutting, taping then shrink wrapping, or run it to your license plate, you still have 5 wires that easily correspond with the harness exactly.

I found the trailer wiring harness at etrailer.com ($13). The HD plug n play costs $60.

I found dual filament bullet style lights on ebay for $20. The low and high watt wires run through the post which doubles as the ground. I just got a wire connection and split the ground to each light (I did the same thing with running wire to the low wattage wire on the light).

The high wattage wire gets its own left or right "run, turn,brake" wire.