Mercury – MP Alert Add-A-Light Kit (Oval) | Expansion Light & Y-Harness | 8M0109505

Overview

If you’re running the Mercury Moving Prop (MP Alert) system and want even better visibility around the transom, this kit makes it easy to expand. The Mercury 8M0109505 MP Alert Add-A-Light Kit lets you add an extra oval smart light—ideal for boats with wide swim platforms, stepped transoms, or layouts where two lights aren’t enough. With the included Y-harness, the new light plugs right into the existing system for quick installation and seamless SmartCraft-controlled activation.

Key Features

• Add-On Smart Light – Includes one oval MP Alert smart light with six bright LEDs.
• Plug-In Expansion Harness – Supplied Y-harness makes it easy to add a third or fourth light.
• SmartCraft-Linked Operation – New light activates automatically when the MP Alert system detects prop movement.
• Enhanced Safety Coverage – Improves visibility for swimmers, divers, and riders near the stern.
• OEM-Grade Build – Weather-sealed light with durable connectors designed for marine conditions.
• Clean Upgrade Path – Works as an extension to existing MP Alert kits without rewiring.

Compatibility

• All SmartCraft-compatible engines
• MP Alert systems (oval-style lights)
• 8M0109507 and other Mercury MP Alert base kits

Performance & Practical Benefits

Adding another smart light increases your boat’s safety zone by making prop-movement warnings visible from more angles. This is especially helpful on boats with broader transoms or swim platforms where swimmers may approach from the sides. The Y-harness keeps installation simple—just plug in, mount the new light, and the system immediately recognizes and activates it whenever the prop is turning. No switches or programming required.

Why Buy OEM

Mercury’s MP Alert system depends on precise SmartCraft communication. OEM smart lights use the correct signaling, LED brightness, waterproof housings, and timing logic to match your existing alert system. Off-brand lights or improvised wiring can cause weak illumination, delayed activation, or system faults. The factory expansion kit ensures the added light works exactly the way Mercury designed it to.

FAQ

Q1: How many additional lights can I add?
This kit allows you to add a third or fourth light to an existing MP Alert system.

Q2: Does the kit include the light?
Yes—one oval smart light and the required Y-harness.

Q3: Will the new light activate automatically?
Yes. It flashes whenever the prop is moving, just like the original MP Alert lights.

Q4: Is it compatible with non-SmartCraft engines?
No. This add-on kit is for SmartCraft-compatible MP Alert systems only.

Q5: Is installation difficult?
No. Plug in the Y-harness, mount the light, connect it—and you’re done.