Mercury – Diesel Engine Unswitched Power Harness 20 Foot | Constant Power Harness | 84-899887T14

The Mercury Diesel Engine Unswitched Power Harness (20 ft) is designed for diesel installations where batteries or power distribution points are mounted far from the engine. It delivers continuous battery power to engine and support systems without relying on ignition-switched circuits, ensuring critical components remain energized at all times.

The 20-foot length supports clean, relaxed routing through large engine rooms and extended hull layouts without splicing or unnecessary extensions. OEM Mercury construction helps maintain stable voltage delivery, protect connector integrity, and support long-term electrical reliability in demanding marine diesel environments.

Key Features

• Unswitched Power Circuit – Supplies constant battery power regardless of ignition position
• 20-Foot Length – Designed for long-distance diesel electrical routing
• Diesel-Specific Electrical Design – Sized for Mercury diesel system loads
• OEM Mercury Construction – Factory connectors and marine-grade wiring for durability

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 systems requiring uninterrupted electrical supply.
• Proper routing helps reduce connector strain and prevent chafing.

FAQs

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

2) When should I choose a 20-foot harness?
It’s recommended when batteries or power distribution points are located far 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 with the engine?
No. This is an unswitched harness and remains powered even when the engine is not running.

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 prevent voltage drop, corrosion, and long-term electrical issues.