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Ignitions and Electrical› Wiring Harnesses

Boomslang

Plug-and-Play Wiring Harness for Haltech Nexus S3 ECU

$960.00 $884.64 Save $75.36

SKU: BF29043-S3

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$100 Minimum Order
Non-Returnable Item
INSTALL DIFFICULTY
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Easy — 1–2 hours

Overview

The Boomslang BF29043-S3 is a plug-and-play wiring harness designed to connect aftermarket engine management systems to your vehicle's factory ECU. It acts as a pre-wired extension, eliminating the need to cut or splice factory wires. This harness is compatible with Haltech Nexus S3 ECUs and offers an easy installation and removal process. It saves time and prevents damage to the original wiring harness.
Show original supplier description
The Boomslang BF29043-S3 is a plug-and-play adapter harness designed to seamlessly integrate aftermarket engine management systems with your vehicle's factory ECU. This harness serves as a pre-wired extension, allowing for the connection of devices like Haltech Nexus S3 ECUs, piggyback controllers, or datalogging systems without any cutting or splicing of the original factory wiring. This installation method preserves the integrity of your vehicle's wiring harness while saving significant time and avoiding the costs associated with hard-wiring. In some applications, the factory ECU may remain in parallel to maintain communication on the OEM CAN bus. The product is suitable for a wide range of Subaru models, including various years of the BRZ, Crosstrek, Forester, FRS, GR86, GT86, Impreza, Legacy, Outback, STI, and WRX. A crucial note from the manufacturer states that Boomslang Fabrication LLC products may be used solely on vehicles used in sanctioned competition and may never be used upon a public road or highway, unless specifically permitted by regulatory exemption. The installer and user are responsible for ensuring compliance with all applicable laws and regulations in the United States. This product is noted as being for manual transmission vehicles in some listings.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandBoomslang
Part NumberBF29043-S3
CategoryIgnitions and Electrical
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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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