HM-FLST Softail Stereo Power Harness 

The HM-FLST Softail 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. It also includes an inline mini-fuse holder near the battery (approx. 10 cm) with a 15A fuse for protected, serviceable power.

We intentionally do not rely on the factory accessory plug, because Softail models vary by year and trim, and that connector is often already in use for heated gear, lighting, or chargers. Instead, we give you control with an in-line on/off switch placed between the tank and the seat so the system can be powered off 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 power takeoff for another low-draw accessory—cleaner, safer, and easier to service than piling more leads onto the battery.

Component Notes (Softail)

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

• Waterproof Deutsch connector plugs into the GP1 for an easy, weather-resistant connection

• In-line on/off switch placed between the tank and the seat for storage shutoff

• Secondary under-seat Deutsch power plug for RGB module (or spare accessory power)

• Inline mini-fuse holder at the battery to protect the harness (15A fuse)