Mercury – Diesel Engine Unswitched Power Harness | 10 Ft | Constant Power Harness | 84-899887T13

The Mercury diesel engine unswitched power harness (10 ft) is designed for diesel installations that require continuous battery power to the engine or related electrical components. Unlike switched harnesses, this circuit remains live at all times, making it essential for systems that must stay powered regardless of engine state. The extended 10-foot length is ideal for boats where batteries or power distribution points are mounted farther from the engine.

This harness allows clean, strain-free routing through the engine room without stretching, splicing, or excess slack. Proper OEM wiring ensures steady voltage delivery while protecting terminals and connectors from long-term stress and corrosion in demanding diesel environments.

Key Features

• Unswitched Power Circuit – Supplies constant battery power at all times
• 10-Foot Harness Length – Supports longer routing distances in larger engine rooms
• Diesel-Specific Design – Built specifically for Mercury diesel electrical systems
• OEM Wiring & Connectors – Correct wire gauge, insulation, and factory-sealed terminals

Engine & Boat Compatibility

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

Important Notes

• Provides constant (unswitched) power and remains live even when the engine is off
• Intended for diesel applications requiring continuous electrical supply
• Proper routing is important to prevent chafing and connector strain

FAQs

1) What is an unswitched power harness used for?
It supplies constant battery power to components that must remain energized, even when the engine is not running.

2) When should I choose a 10-foot harness?
Choose a 10-foot harness when batteries or power distribution points are located farther from the engine and shorter harnesses would be stretched or require splicing.

3) Can this harness be used with DTS systems?
Yes. It is compatible with Mercury diesel engines using both mechanical and DTS control systems.

4) Does this harness turn off with the engine?
No. This is an unswitched harness and remains powered at all times.

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