Ignitions and Electrical› Wiring Harnesses

Kmj

BIG 3 Wiring Upgrade Kit

$134.99

SKU: KMJB3WU

In Stock
In Stock
Ships by Sep 12
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Easy — 1–2 hours

Overview

The KMJ BIG 3 Wiring Upgrade Kit is a 1/0 gauge cable kit designed to upgrade your vehicle's power and ground connections. This kit is necessary for vehicles with higher amperage draws, such as those with upgraded fuel systems, audio systems, or intercooler pumps and fans. It also includes an inline fuse holder.
Show original supplier description
The KMJ BIG 3 Wiring Upgrade Kit is essential for vehicles experiencing increased electrical demand from components like upgraded audio systems, fuel pumps, or intercooler fans. This kit enhances your vehicle's charging system by upgrading the main power and ground connections with 1/0 gauge, all-copper welding cable, ensuring maximum conductivity. It also incorporates an inline fuse holder for added safety and system protection. Constructed from all-copper, USA-made welding cable, this kit provides superior performance compared to cheaper copper-clad aluminum (CCA) alternatives, offering double the amperage rating. The cables are custom-cut to ensure a perfect fit for your specific application, minimizing excess wiring and guaranteeing optimal connections. Installation involves working with your vehicle's charging system, and care must be taken to insulate and secure power wires away from hot or moving parts to prevent fires. While professional installation is recommended, KMJ Motorsports acknowledges that many enthusiasts prefer DIY installations but is not liable for damages resulting from improper installation. This kit is specifically designed for 1984-2004 Mustangs. Proper cable lengths are determined by the specific year and trim (e.g., GT, Cobra, Mach 1) of your Mustang, so please provide this information during checkout. The kit is a must-have when upgrading to a higher amperage alternator and will also work with your OEM alternator.

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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Available on iOS & Android

Specifications

BrandKmj
Part NumberKMJB3WU
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.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

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