Engine Harness

The engine-to-cab harness is the backbone of any successful semi truck engine conversion—ensuring seamless communication between your new Caterpillar, Cummins, or Detroit Diesel ECM and the chassis electronics. Mismatched or generic wiring can lead to gauge failures, switch issues, and unnecessary downtime, but Kustom Truck Parts delivers custom engine harnesses and semi truck wiring harnesses engineered specifically for conversions and swaps in Kenworth, Peterbilt, Freightliner, Western Star, and Sterling heavy-duty chassis.

Our lineup includes purpose-built solutions across these platforms:

• Adapter Harnesses — Cost-effective Caterpillar-to-Caterpillar bridges for analog cabs
• Legacy Harnesses — Generic kits for mechanical-to-electronic repowers
• NAMUX-Series Harnesses (NAMUX1–NAMUX4) — Chassis-specific for 2006+ multiplexing (J1939 integration, DEF/SCR support)
• Pre-NAMUX Harnesses — Pure analog for pre-2005 classic chassis
• Sensor Harnesses — Serial-specific OEM replacements for Cat 3406E/C15

Supporting ECM generations from Caterpillar ADEM2–ADEM4, Cummins Celect through CM2450, and Detroit DDEC3–DDEC5, each harness is designed for direct-fit reliability—delivering factory-like dash function (gauges, switches, cruise, Jake brakes) as if the engine were original. We also offer fully custom builds for unique one-off projects.

Browse the subcategories below to match your engine and chassis combo—superior durability and precise fitment. Unsure about compatibility or need serial number verification? Contact our team for expert guidance on your conversion project.