HM-RK Road King Stereo Power Harness

The HM-RK Road King Stereo Power Harness is purpose-built to power the GP1 gauge head unit the right way: direct to the battery with dedicated power and ground so you’re not tapping into the bike’s factory wiring.

This harness plugs into the GP1 in the headlight nacelle with a waterproof Deutsch connector and runs straight back to the battery with ring terminals for a clean, reliable supply.  Includes an inline mini-fuse holder near the battery (approx. 10 cm) with a 15A fuse for protected, serviceable power.

We intentionally do not use the accessory plug under the seat, because on most Road Kings that plug is already spoken for (heated gear, lighting, chargers, etc.). That means the GP1 won’t be tied to the factory nacelle toggle but we still give you control with an in-line on/off switch placed between the tank and the seat so the system can be shut down during storage, preventing parasitic draw and helping protect your battery when the bike sits.

This harness also includes a secondary waterproof Deutsch power connector under the seat. The intent is to power the RGB lighting module without stacking extra ring terminals on the battery. If you’re not running RGB, that same under-seat connector becomes a spare keyed power takeoff for another low-draw accessory—cleaner, safer, and easier to service than piling more leads onto the battery.

Component Notes

• Direct-to-battery power + ground (no factory splice) with inline fuse

• Waterproof Deutsch Connector plugs into the GP1-RK for an easy waterproof connection. 

• An in-line on/off switch is placed between the tank and the seat so the system can be shut down during storage, preventing parasitic draw and helping protect your battery when the bike sits.

• Secondary under-seat Deutsch power plug for RGB module (or spare accessory power) Inline automotive fuse at the battery to protect the harness