Mercury – MP Alert Harness Extension | 20-Foot Forward Routing Cable | 84-8M0054185

Overview

Some MP Alert installations call for a forward-mounted warning light—especially on larger boats where people may approach from the bow or spend time in front-facing swim areas. The Mercury 84-8M0054185 MP Alert Harness Extension gives you 20 feet of reach to run an MP Alert light toward the front of the boat, making the Moving Prop warning visible from more angles. It plugs directly into the existing MP Alert wiring for a clean, reliable extension.

Key Features

• 20-Foot Extension Harness – Long enough for bow or forward-deck MP Alert light placement on bigger boats.
• Plug-and-Play Design – OEM connectors allow quick installation with no splicing or modification.
• Expanded Safety Visibility – Helps place the MP Alert light where swimmers and riders can see it sooner.
• Flexible Routing Options – Extra length makes it easy to pass through bulkheads, gunwales, or side panels.
• Marine-Durable Build – Sealed cable and connectors built to handle vibration, moisture, and everyday conditions.

Compatibility

• All Mercury MP Alert systems using oval smart lights
• SmartCraft-compatible engines
• MP Alert Add-A-Light kits and Y-harness expansion setups
• Boats needing forward-mounted Moving Prop alerts

Performance & Practical Benefits

This harness gives you the reach needed to add or relocate an MP Alert light far forward on the boat. By extending the visible warning zone, you help swimmers and passengers recognize prop-movement danger before getting close to the stern. The 20-foot length allows clean, strain-free routing through long rigging channels, keeping the installation tidy and protected from wear. Once installed, the light activates automatically with the rest of the MP Alert system.

Why Buy OEM

Mercury’s MP Alert system relies on sealed, properly pinned connectors to deliver reliable activation timing and strong LED output. The OEM extension harness ensures your forward-mounted light works exactly as intended—without flicker, delay, or moisture intrusion. Aftermarket extensions often fall short in marine environments, but the factory harness is built to last.

FAQ

Q1: When would I choose the 20-foot extension instead of the 10-foot?
For larger boats or longer helm-to-bow routing paths where the shorter harness won’t reach cleanly.

Q2: Does this extension affect MP Alert light performance?
No. It simply extends the wiring—the system activates normally.

Q3: Can this be used with Y-harness add-on kits?
Yes. It works with any MP Alert expansion setup using oval smart lights.

Q4: Does it work on non-SmartCraft engines?
This extension is for MP Alert systems tied to SmartCraft-compatible engines.

Q5: Is installation difficult?
No. Plug it in and route it like any other harness—no rewiring needed.