Overview

The Hella Marine 357211011 is a two-light wiring harness that powers and switches a pair of auxiliary LED lights or light bars on a 12V DC system. It supports up to 150W per light at 12V (300W total) and uses a 12V relay so the control switch at the helm only carries low current.

This kit helps keep a clean install on a boat by giving you long leads to reach common mounting points, plus fused power from the battery and a dedicated relay for the lighting load. The harness is finished in black, which tends to blend in well when routed under a hardtop, inside a console, or along a cable run.

Key features

• Supports two lights up to 150W each at 12V (300W total)
• 12V relay included to keep the high-current path out of the switch and dash wiring
• Main feed includes a 30A fuse for circuit protection
• Two 10 ft (315 cm) light leads for reaching common mounting locations on T-tops, arches, rails, and bow areas
• DT connector on the harness for secure plug-in connections
• Switch included for simple on and off control from the helm

Installation and setup

Mount the relay in a protected spot close to the battery or distribution area, then route the two light leads to each fixture. On boats, take the extra minute to support the harness every few inches, keep it away from hot engine components and moving linkages, and use chafe protection where it passes through bulkheads or metal.

Seal any terminations that sit in damp areas and leave a drip loop where the wiring drops into a console. A small amount of dielectric grease on exposed connections helps when the install lives in salt air and gets regular washdowns.

Electrical and system integration

This harness is for 12V DC lighting circuits. If your vessel is 24V, the lights and harness must be supplied with a proper 12V feed, and the combined load still needs to stay within the 300W limit. Before finalizing the run, add up the actual wattage or current draw for both lights so you stay inside the fuse and relay capacity.

Use cases on board

This harness is a good fit when you want two auxiliary lights on one switched circuit, such as a pair of deck or cockpit work lights, docking lights mounted forward, or twin flood/spot lights on a hardtop. It works well for owners who want a straightforward, relay-controlled install without building a harness from scratch.

What’s included

• Wiring harness with DT connector and 30A fuse
• 12V relay
• Switch
• Mounting instructions