Automotive wiring harnesses are among the most critical components in vehicles, with their quality, safety, and reliability directly impacting overall vehicle performance. Harness failure can lead to signal transmission interruptions, functional device malfunctions, overheating or fire hazards from excessive contact resistance, short circuits, or insulation breakdown causing electrical leakage. To ensure wiring harness quality, safety, and reliability, rigorous testing is essential both during production and before end-user deployment. This overview, compiled by FAB Lab, outlines key testing contents and applicable standards:
1. Complete Vehicle Wiring Harness Compliance: QC/T29106-2014
This standard specifies technical requirements for automotive low-voltage wiring harnesses, including:
- 1.1 Dimensional inspection criteria
- 1.2 Material and component performance requirements
- 1.3 Terminal-to-harness connection methods and post-connection specifications
- 1.4 Terminal-to-harness junction requirements
- 1.5 Sealing plug integrity: No visible gaps between wires/sealing plugs or plugs/housing during crimping
- 1.6 Bundling specifications: Harnesses must be tightly and uniformly wrapped without loosening. Protective sleeves must remain stationary during bending
- 1.7 Assembly accuracy: Components must be correctly assembled without misalignment; terminals must not dislodge from housings
- 1.8 Electrical continuity: 100% continuity with no short circuits or misroutes
- 1.9 Environmental resistance testing:
- High/low temperature cycling
- Humidity resistance
- Vibration resistance
- Salt spray resistance
- Industrial solvent resistance
2. Crimping Requirements: QC/T29009-1991
Key crimping inspection and test procedures include:
- 2.1 Visual inspection: Joint surfaces must be clean with no burrs or sharp edges; joints must withstand assembly forces without cracking
- 2.2 Humidity resistance test: Conducted at 40±2°C with 90-95% RH for 100 hours, followed by 24-hour ambient drying. Contact reliability must be maintained post-test
- 2.3 Joint pull-out test: Apply specified static tension (via weights or force gauges) to terminals for 10 seconds
- 2.4 Voltage drop test: Conducted after humidity resistance testing
3. Battery Cable Terminal Requirements: QC/T29013-91
Specifies dimensional requirements for battery cable terminals connecting to positive/negative posts
4. Connector Standard: QC/T417.1-2001
Defines automotive wiring harness connector terminology, test methods, and general performance requirements
5. Central Electrical Box Requirements: QC/T707-2004
Specifies technical conditions for vehicle central electrical junction boxes:
- 5.1 Operating temperature ranges:
- -40°C to 70°C (interior)
- -40°C to 110°C (under-hood)
- 5.2 Storage temperature ranges:
- -40°C to 90°C (interior)
- -40°C to 130°C (under-hood)
- 5.3 Type tests: Include performance verification and environmental resistance testing
6. Wire Material Standards: QC/T730-2005
Specifies requirements for thin-wall insulated low-voltage automotive wires, including:
- 6.1 Electrical performance:
- DC conductor resistance
- Insulation integrity
- Dielectric strength
- Volume resistivity
- 6.2 Mechanical performance:
- High-temperature pressure resistance
- Stripping force testing
- 6.3 Low-temperature performance:
- Cold bend testing
- Impact resistance at low temperatures
- 6.4 Abrasion resistance testing
- 6.5 Thermal aging tests:
- Short/long-term aging
- Heat shrinkage
- Thermal overload resistance
- 6.6 Environmental/chemical resistance:
- Fuel/oil resistance
- Marking durability
- Ozone resistance (192h crack-free)
- Hot water resistance (1kV withstand voltage post-test)
- Humidity resistance (1kV withstand voltage post-test)
- 6.7 Flame retardancy: Wires must self-extinguish within 70s after flame removal, with minimum 50mm unburned insulation remaining
This comprehensive testing regime ensures automotive wiring harnesses meet stringent safety and performance benchmarks, safeguarding vehicle functionality and occupant safety across all operating conditions.
