![XD-SPD-SLV Xtreme-Duty Complete Wiring Kit, 8 ft. Switch Cable Length [Silver Switch Bezel]](https://www.jegs.com/images/mini_750/500/572/572-xd-spd-slv.jpg)
XD-SPD-SLV Xtreme-Duty Complete Wiring Kit, 8 ft. Switch Cable Length [Silver Switch Bezel]
K&R Performance Engineering XD-SPD-SLV Features:
Built for the harshest conditions, the XTREME DUTY Complete Wiring Kit is a ground-up redesign engineered for extreme environments where reliability is non-negotiable. Featuring a newly upgraded fuse and relay panel with stronger relays and optimized circuitry, this is the most rugged and complete wiring system available.
The redesigned switch panel adds fuel pump Prime capability along with Aux 1 and Aux 2 outputs for expanded accessory control, all while maintaining the same compact footprint as the Super-Duty system. Installation is faster and cleaner thanks to a plug-and-play cable assembly that connects the switch panel directly to the fuse/relay panel—eliminating switch-to-relay clutter and drastically reducing wiring time.
For added versatility, the rear of the switch panel includes dedicated convenience terminals for powering gauges, switches, lighting, accessories, and grounds. Like all K&R switch panels, it also features rear-mounted white LEDs that automatically illuminate in interior mode for clean, professional lighting.
The XTREME-DUTY Wiring System, like its Super-Duty predecessor, comes fully loaded with color-coded, clearly labeled GXL wiring—so installation is faster, cleaner, and mistake-free. Included labeled circuits cover every critical function, including:
- Ignition
- Fuel Pump (12ga)
- Fan (12ga)
- Water Pump
- Delay Box (14ga)
- Transbrake (14ga)
- Throttle Stop
- Pro-Stage
- Lights
- Starter
- Tach
- RPM Switch
- 2-Step
- Shift Timer
- Water Temp
- Aux 1 and Aux 2
Additional unlabeled color-coded wires are provided for advanced and custom applications, including:
- Ground
- Air/Spring Shifter
- Neutral Safety
- Remote Start
- Crank Trigger
- Coil Wires
- Alternator (8ga)
- Ignition Power & Ground (10ga)
- Pre-terminated Main Power Wire (6ga)
Every XTREME-DUTY kit also includes all required high-quality terminals, heat shrink, wire ties, and a full-color, laminated POSTER-SIZED wiring diagram for easy reference during installation. New for this system is a bolt-down inline 100-amp fuse for both the main power feed and alternator wiring—adding an extra layer of safety and reliability.
Dimensions:
- Fuse Panel:
- Overall - 7" x 5"
- Vibration Mounts - 6.3" x 4.3"
- Switch Panel
- Overall - 8.25" x 3"
- Mounting Holes - 7.6" x 2.4"
Rugged & Reliable K&R Performance Engineering Xtreme-Duty Complete Wiring Kits
The K&R Performance Engineering Xtreme-Duty Complete Wiring Kit is a top-tier, heavy-duty race car wiring harness system engineered for simplicity, durability, and total electrical control. Designed for high-performance environments, this kit delivers a fully integrated switch panel and fuse/relay setup with pre-labeled, color-coded wiring that dramatically reduces installation time and minimizes clutter under the dash. Perfect for performance builders and chassis shops, the Xtreme-Duty kit is known as one of the most rugged and comprehensive harness systems available at its price point — ideal for drag racing, off-road, or custom high-performance builds.
Kits feature all required wires (fuel pump, fan, starter, tach, lights, delay box, 2-step, water temp, and more) in durable GXL insulation, terminals, heat shrink, wire ties, and a poster-sized wiring diagram to ensure a professional, clean installation. It even includes heavy-duty main power and alternator fuses. Multiple accessory circuits such as Prime fuel pump and dual Aux outputs, along with convenience terminals for gauges, lights, grounds and more — plus white LED indicators that illuminate with interior power.



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