A wiring harness is a bundled assembly of electrical wires, connectors, and terminals that carries power and signals between the components of a commercial vehicle.

It organizes many circuits into one routed loom so current and data reach lights, sensors, switches, and control units reliably, while protective sleeving guards the wires against heat, vibration, and abrasion.

Harnesses run throughout a truck or bus — engine bay, chassis, cab, and lighting circuits. Because a damaged or corroded harness can disable safety-related systems, electrical repairs are best checked by a qualified technician.