Wiring Harnesses

Want to connect a new engine management system to your engine without cutting the original wires? This category contains ready-made engine harnesses, adapter harnesses and extensions for ECUs, sensors and motorcycle handlebars – for you who want a neat and reliable electrical project.

What a wiring harness does

A wiring harness brings together wires, connectors and terminals for a specific task, e.g. the connection between the ECU, sensors, injection and ignition. Here you will find complete engine harnesses, e.g. Rywire Honda B-Series Mil-Spec, plug-and-play adapter harnesses and universal wire-in harnesses from Haltech, as well as extensions for handlebar switches and turn signals from NAMZ. FAST and Fleece Performance are also available in this category.

How to choose a wiring harness

• Plug-and-play or wire-in: an adapter harness typically plugs into the car's original connectors, while a universal harness requires you to terminate and connect the wires yourself.
• Connectors and ECU: check that the connectors fit both your ECU and the car's harness – some harnesses require an extra adapter, which is stated in the product name.
• Length and routing: choose a length that leaves room to route the harness away from heat and moving parts.
• Expansion: if you need more sensors or outputs, an IO expansion harness can be relevant, depending on the ECU.

Looking for harnesses made for a specific model? Also see vehicle-specific wiring harnesses.

Installation and durability

Disconnect the battery before starting work, and check the connectors for corrosion and bent pins. Protect the wires with wire loom, and use suitable connectors and terminals if you extend or modify. Misfires or incorrect sensor readings can be caused by a poor connection, so check the joints first when troubleshooting.

Frequently asked questions

What is the difference between plug-and-play and wire-in harnesses?

A plug-and-play harness typically connects directly to the car's original connectors, so the installation can be done without cutting. A wire-in harness comes with open wire ends that you have to connect yourself – this gives freedom but requires more electrical experience.

Can I install an engine harness myself?

It depends on the harness and your experience. An adapter harness can often be installed with basic tools, while a complete engine harness or a wire-in solution requires a crimping tool, a wiring diagram and careful checking. If in doubt, get an auto electrician to help.

Why do some harnesses require an adapter?

Some harnesses have connectors for a different ECU generation than the car's, e.g. an engine harness with OBD1 ECU connectors. An adapter is then needed in between before it fits. Always check the product description for the specific part number.