hi,can anyone help me please.i have just fitted a classic tow bar to my 1300.i have a small cargo trailer already wired.but havnt got a clue how to wire the bike .
We have a sticky in this section for that:
https://www.st-owners.com/forums/sh...ng-diagram-Trailer-Isolation-Relay-on-ST-1300
For now I think this is still available from Open Road Outfitters HERE. This is the same Universal Trailer Harness originally sold by EC. There should be other vendors that sell the same type of item as Mellow stated. Just look for isolated motorcycle trailer harness. The isolated part is important to avoid issues with the bike factory systems and wires.
Edit: Amazon and Kuryakyn also have the Kuryakyn Universal Trailer Harness.