Mercury – Malfunction Light Harness | 25-Foot Single-Helm Cable | 84-8M0048056

Overview

Catalyst-equipped MerCruiser engines rely on a clear dash-mounted warning light to alert you when the emissions system needs attention. The Mercury 84-8M0048056 Malfunction Light Harness gives you a full 25 feet of cable—ideal for single-helm boats with longer console runs or more complex routing paths. Once installed, it provides a clean, dependable connection so the catalyst malfunction light illuminates the moment the OBDM system detects a fault.

Key Features

• 25-Foot Harness – Designed for longer single-helm layouts that need extended routing distance.
• OBDM Alert Path – Connects the engine’s catalyst fault signal directly to the dash-mounted warning light.
• Catalyst Engine Ready – Fits all MerCruiser engines equipped with a catalyst system.
• OEM Mercury Connectors – Ensures secure engagement and proper pin alignment.
• Flexible Marine Cable – Routes easily through rigging tunnels, bulkheads, and tight helm spaces.
• Reliable Alert Delivery – Ensures the malfunction light activates promptly when service is needed.

Compatibility

• All MerCruiser catalyst-equipped engines
• Dash-Mounted Catalyst Malfunction Light (8M0046481)
• Single-helm installations that require a 25-foot harness

Performance & Practical Benefits

This harness gives you the extra reach needed for clean, stress-free routing from the engine compartment all the way to the helm. Once connected, it keeps the catalyst warning light tied directly into the diagnostic system, giving you a quick visual cue—much like a check-engine light—whenever the catalyst requires inspection. It’s a simple, reliable way to stay ahead of potential emission-system issues.

Why Buy OEM

Catalyst warnings aren’t something you want to trust to generic wiring. Mercury’s OEM harness matches the engine’s electrical logic and provides solid shielding, preventing false alerts or missed warnings. Off-brand cables often struggle with poor fit or noise interference, but the factory harness ensures dependable alert behavior in real marine conditions.

FAQ

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

Q2: Why choose the 25-foot version?
It’s ideal for longer console layouts where shorter harnesses won’t reach cleanly.

Q3: Will it work with all MerCruiser engines?
It works on any catalyst-equipped MerCruiser engine.

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

Q5: Is installation difficult?
Installation is straightforward—plug in the OEM connectors and route like any standard helm harness.