Mercury – Diesel Engine Unswitched Power Harness | 15 Ft | Constant Power Harness | 84-8M0150523

The Mercury diesel engine unswitched power harness (15 ft) is designed for diesel installations that require continuous battery power to the engine or supporting electrical systems. This harness supplies always-on power and does not switch off with the engine, making it essential for diesel components that must remain energized at all times. The extended 15-foot length is ideal for larger engine rooms where batteries or power distribution points are positioned farther from the engine.

By eliminating the need for splices or extensions, this harness supports clean, relaxed routing and reduces strain on connectors. OEM diesel-specific wiring ensures steady voltage delivery while protecting sensitive electrical components from long-term wear, corrosion, and voltage loss.

Key Features

• Unswitched Power Circuit – Provides constant battery power at all times
• 15-Foot Harness Length – Designed for extended routing in larger engine rooms
• Diesel-Specific Electrical Design – Sized for Mercury diesel electrical loads
• OEM Wiring & Connectors – Factory-sealed terminals with marine-grade insulation

Engine & Boat Compatibility

• Mercury diesel engines
• Mechanical control systems
• DTS (Digital Throttle & Shift) control systems

Important Notes

• Supplies constant (unswitched) power and remains live even when the engine is off
• Intended only for diesel applications requiring continuous electrical supply
• Proper routing helps prevent chafing and connector stress

FAQs

1) What is an unswitched power harness used for?
It delivers continuous battery power to diesel engine systems or components that must remain energized at all times.

2) When should I choose a 15-foot harness?
Choose a 15-foot harness when batteries or power distribution points are located farther from the engine and shorter harnesses would require extensions or splicing.

3) Is this harness compatible with DTS systems?
Yes. It supports Mercury diesel engines using both mechanical and DTS control systems.

4) Does this harness shut off when the engine stops?
No. This is an unswitched harness and remains powered continuously.

5) Why use an OEM Mercury harness instead of aftermarket wiring?
OEM harnesses use the correct wire gauge, sealed connectors, and diesel-rated insulation to help prevent voltage drop, corrosion, and long-term electrical failures.