Hybrid Racing K Swap Conversion Harness for 1999-20000 Civic

Hybrid Racing K Swap Conversion Harness for 1999-2000 Honda Civic

Wiring is where K swaps stall. The engine's on the mounts, the axles are in, and then the project sits for a month while you stare at two harnesses that don't speak the same language. We built this conversion harness to delete that month. It connects your 99-00 Civic's factory dash harness to an OEM K-series engine harness and K-series ECU, true plug and play, and your factory gauge cluster keeps working like Honda intended.

We've been building these for over ten years, and this harness is powering thousands of K swaps worldwide. Unlike companies that make you cut up and mail in sections of your stock harness, ours arrives fully assembled and tested, no core exchange, no downtime. We build every harness with brand-new connectors, terminals, and wiring sourced from the same manufacturer Honda uses, machine-crimped with no soldered joints, and human-checked before it ships. Every wire is labeled, so the install goes clean the first time.

Compatibility matters here, so read this part twice. This harness works with all USDM and JDM 02-04 K-series engine harnesses and ECUs, including K20A, K20A2, and K20A3. It does not work with 05-06 engine harnesses or ECUs, and it does not work with K24 harnesses or ECUs. If you're running UKDM wiring, you'll need to adapt the wideband O2 sensor to narrowband. When in doubt, call us before you order and we'll sort out exactly what your combination needs.

Key Features

• Built for K-series swaps in the 1999-2000 Honda Civic (EK chassis, EM1 Si included)
• Works with USDM and JDM 02-04 K-series engine harnesses and ECUs (K20A, K20A2, K20A3)
• Retains full factory gauge cluster functionality
• True plug and play: no cutting, splicing, or core harness exchange
• All-new connectors, terminals, and wiring from Honda's own supplier
• Machine-crimped, no soldered joints, human-checked before shipping
• Every wire labeled for a clean, organized install
• Full replacement warranty
• Free phone and email tech support from people who've wired these swaps for a decade

Fitment

This harness is chassis and year specific. If your Civic is a 96-98, or you're swapping an EG, EF, or DC2, we make conversion harnesses for those too; grab the one that matches your chassis and year.

What to Know Before You Buy

The harness handles the wiring, so make sure the rest of the swap list is covered: mounts, axles, shifter and cables, fuel system, and a 02-04 K-series ECU to match. We stock all of it, and if you're starting from zero, our K swap packages bundle the big pieces so nothing shows up incompatible. The single most common mistake we see is buying a 05-06 or K24 engine harness to save money and expecting it to work with this conversion harness. It won't. Match the harness and ECU to 02-04 K20 spec and the wiring day of your swap becomes the easy day.