Automotive Secondary Wiring Harness Market: Market Size & Forecast 2026

A secondary wiring harness routes power and data between a vehicle's main electrical architecture and sub-assemblies such as lighting, instrument clusters, infotainment, HVAC controls, sensors and body control modules, complementing the primary harness that links the battery, engine and chassis systems. The market is estimated at around USD 69.5 billion in 2025 and is projected to grow at approximately 5.0% per year through 2030. Volume growth is being reinforced by rising per-vehicle wiring content, even as unit production in some mature regions plateaus.

• •Global market size estimated at USD 69.5 billion in 2025 with a ~5.0% CAGR through 2030.
• •Secondary harnesses sit below the primary harness in the vehicle electrical architecture.
• •Average harness content per vehicle continues to rise with added electronic features.

Electrification of powertrains is the single largest growth driver, as battery electric and hybrid vehicles require additional high- and low-voltage harnesses for battery packs, inverters, onboard chargers and thermal management. Rising consumer demand for connected, comfort and advanced driver-assistance features is increasing the number of ECUs, sensors and actuators that must be wired. Stringent safety, lighting and emissions regulations, particularly in Europe, North America and China, are pushing adoption of LED lighting, smart sensors and zonal electronic architectures.

• •BEV and HEV models require more and more complex harnesses than ICE vehicles.
• •ADAS, infotainment and connectivity features raise wire and connector count per car.
• •Regulations on lighting, emissions and safety are expanding required electronic subsystems.

By vehicle type, passenger cars hold the dominant share of revenue, while commercial vehicles and electric vehicles are the fastest-growing segments due to fleet electrification and last-mile delivery trends. By application, body and lighting harnesses represent the largest categories, followed by cabin/infotainment, HVAC, door and engine-peripheral harnesses. Geographically, Asia-Pacific leads on the back of large vehicle production bases in China, Japan, South Korea and India, with North America and Europe following, and emerging manufacturing hubs in Southeast Asia and Eastern Europe gaining share.

• •Passenger cars dominate, with EVs and commercial vehicles growing fastest.
• •Body, lighting and cabin/infotainment harnesses are the largest application segments.
• •Asia-Pacific holds the leading regional share, supported by China, Japan, South Korea and India.

What are the recent trends and outlook?

The shift toward zonal and centralized vehicle electrical architectures is reducing total harness length and complexity while increasing the value of high-speed data and high-voltage cable assemblies. Lightweight aluminium conductors, flat Ethernet cables and automated harness assembly are gaining traction as OEMs target weight, cost and reliability improvements. Through 2030, the market is expected to continue expanding at a mid-single-digit pace, supported by EV adoption, software-defined vehicle features and ongoing growth in Asia-Pacific production.

• •Zonal architectures are reshaping harness design toward shorter, higher-data-rate cable runs.
• •Aluminium conductors and automotive Ethernet are emerging to cut weight and bandwidth limits.
• •Long-term outlook remains positive, anchored by EV penetration and rising electronic content per vehicle.