Mercury – Malfunction Light Harness | 15-Foot Single-Helm Cable | 84-8M0048054

Overview

Catalyst-equipped MerCruiser engines need a clean and dependable connection to the dash-mounted malfunction light, and this harness provides exactly that. The Mercury 84-8M0048054 Malfunction Light Harness gives you fifteen feet of length—ideal for single-helm boats that require a longer routing path from the engine compartment to the dash. Once installed, it ensures the catalyst warning light comes on the moment the OBDM system detects a fault, giving you the same kind of early alert you’d expect from a check-engine light in a vehicle.

Key Features

• 15-Foot Extension – Designed for single-helm layouts that need more reach than standard harnesses.
• OBDM Signal Path – Carries catalyst malfunction alerts directly to the dash indicator light.
• Catalyst-Engine Compatible – Built for all MerCruiser engines equipped with a catalyst system.
• OEM Connector Fit – Factory Mercury connectors ensure proper pin alignment and a secure connection.
• Flexible Routing Design – Long enough to run through consoles, rigging tunnels, and tight bulkhead spaces.
• Reliable Alert Delivery – Ensures the malfunction light activates accurately when service is required.

Compatibility

• All MerCruiser catalyst-equipped engines
• Dash-mounted Catalyst Malfunction Light (8M0046481)
• Single-helm installations requiring a 15-foot harness

Performance & Practical Benefits

With extra length for more complex helm layouts, this harness allows for clean, strain-free routing from the engine to the dash. It keeps the malfunction light tied directly into the catalyst monitoring system, ensuring you see an alert right away if the engine logs a catalyst-related fault. It’s an easy way to maintain proper oversight of the emissions system without adding a complex display.

Why Buy OEM

Catalyst alerts are tied to important emissions and engine-protection functions. Mercury’s OEM harness ensures the warning light receives a clean, accurate signal. Knockoff harnesses often suffer from loose connections or incorrect wiring, which can lead to false alarms or no alarm at all. The OEM version is built with proper shielding, durable connectors, and the right electrical logic for long-term reliability.

FAQ

Q1: What does this harness actually connect?
It links the engine’s OBDM catalyst-alert signal to the dash-mounted malfunction light.

Q2: Why choose the 15-foot version?
It’s ideal for single-helm boats that need a longer harness to reach the dash cleanly.

Q3: Does this harness fit all MerCruiser engines?
It fits only catalyst-equipped MerCruiser engines.

Q4: Is the malfunction light included?
No. The light is sold separately as part number 8M0046481.

Q5: Is installation complicated?
No. It plugs in using OEM connectors and routes like any standard dash harness.