Kuryakyn 2576 Honda GL1800 trailer hartness wiring plug and play 4 wires plus extra power for trailer fits 2018 up models for alrm light etc too!  Eliminate overloading stock lighting or accessory circuits. The Kuryakyn Trailer Wiring & Relay Harness utilizes inputs from the motorcycle to direct power away from the battery to the appropriate trailer circuit. see earler models too-

• 4-Wire Plus 1: Provides standard4-wire output (run, left turn/brake, right turn/brake, ground), includes flat-4 connector
• Harnesses contain a "bonus wire" to provide fused 12v power to the trailer for compartment lights or security keyless entry systems  ****  Was  £143 !!!   last one grab a bargain

Plug and Play harness!

Kuryakyn 2576 Hinda GL1800 trailer hartness wiring plug and play 4 wires plus extra power for trailer for alrm light etc too!  Eliminate overloading stock lighting or accessory circuits. The Kuryakyn Trailer Wiring & Relay Harness utilizes inputs from the motorcycle to direct power away from the battery to the appropriate trailer circuit.

• 4-Wire Plus 1: Provides standard4-wire output (run, left turn/brake, right turn/brake, ground), includes flat-4 connector
• Harnesses contain a "bonus wire" to provide fused 12v power to the trailer for compartment lights or security/keyless entry systems