Marine Tech - Yamaha Test Harness Blog

When troubleshooting electrical problems, a test harness allows you to measure voltages and resistances without cutting and splicing harnesses. The harness connects into the motor wiring so you can measure the component while the motor is running.

We carry an assortment of 3 pin, 4 pin, and 6 pin harnesses for use on your Yamaha motor. Once you’ve diagnosed the electrical issue, you’ll be well on your way to solving it and getting back out on the water.

Installing and Using a Test Harness on Your Yamaha Engine

Although test harnesses are mostly just wires, those wires make up a unit that is manufactured to fit a specific application. It has shape and connectors, and each measures a specific function of your Yamaha engine.

Installing the harness in line with the existing electrical system is easy, but you do need some intermediate knowledge to understand the results. Be sure to reference your service manual to ensure you can read and interpret the measurements correctly. You will also need a digital multimeter with Min/Max recording.

Yamaha Test Harness Options

We offer a number of test harnesses to fit your Yamaha engine needs. Each product is listed with its corresponding Yamaha part number for easy reference.

Yamaha 3 Pin Test Harness (AMT06846)

Yamaha equivalent part number: YB-06846, 90890-06846
Used to test for continuity in the rectifier/regulator.

Yamaha 3 Pin Test Harness (AMT06926)

Yamaha equivalent part number: YB-06926

Yamaha 3 Pin Test Harness (AMT06869)

Yamaha equivalent part number: YB-06869, 90890-06869
For use with Yamaha 4-stroke engine harness and pressure sensors. Connects to sensors for oil pressure, water pressure, manifold pressure, and other similar sensors on the 4-stroke engine harness.
Enables hands-free measurement of voltage and resistance.
Connects safely and securely to multimeter probes without risk of damage to delicate pins and terminals.

Yamaha 4 Pin Test Harness (AMT06871)

Yamaha equivalent part number: YB-06871, 90890-06871
For use with a digital voltmeter to test the voltage output of the rectifier/regulator.

Yamaha 6 Pin Test Harness (AMT06872)

Yamaha equivalent part number: YB-06872, 35-06872
For use with a digital voltmeter and peak voltage adapter to measure pulser coil output voltage.

Yamaha 100 Hour Service

Follow along on our YouTube channel as we walk you through a Yamaha 100 Hour Service on your 4-stroke motor. You’ll learn how to perform regular maintenance on your motor to keep it in reliable operation and find any pending issues that could ruin your boating season. Includes changing and checking engine oil and oil filter, fuel filters, spark plugs, and lower unit gear oil. This is the perfect DIY for a beginner and will give you more familiarity and confidence working with your Yamaha motor.

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