Automotive connectors and wiring harnesses are an indispensable part of the modern vehicle, carrying electrical signals and power. USCAR, the United States Council for Automotive Research, is an organisation that develops and promotes automotive industry standards. This article looks at the importance of USCAR standards for automotive wiring harnesses and their applications in the industry.

1. About USCAR

USCAR standards are drafted jointly by Stellantis, Ford and General Motors. Its mission is to promote technical cooperation and standardisation in the automotive industry to improve competitiveness and efficiency across the sector. One of its important roles is developing standards for automotive connectors and wiring harnesses.

2. USCAR standards for automotive connectors and harnesses

USCAR has many standards on automotive wiring harnesses. A brief introduction to the harness related ones follows.

1. USCAR 1, Salt Spray Testing and Evaluation of Fastener Finishes.

2. USCAR 2, Performance Specification for Automotive Electrical Connector Systems, one of the most commonly used connector standards.

3. USCAR 12, Electrical Connector Design Criteria.

4. USCAR 17, Performance Specification for Automotive RF Connector Systems, the most commonly used test standard for FAKRA connectors.

5. USCAR 18, FAKRA SMB RF Connector Supplement.

6. USCAR 19, Coaxial Cable Connector Interface - Square Outer Conductor.

7. USCAR 20, Field Correlated Life Test Supplement to SAE/USCAR-2.

8. USCAR 23, Road Vehicles - 60 V and 600 V Single Core (ISO/Metric) Cables - Dimensions, Test Methods and Requirements.

9. USCAR 21, Performance Specification for Cable-to-Terminal Electrical Crimps, one of the most commonly used terminal standards.

10. USCAR 25, Electrical Connector Assembly Ergonomic Design Criteria.

11. USCAR 26, Test Procedure for Electrical Ground Attachments.

12. USCAR 29, Automotive Grade Coaxial Cable Performance Specification.

13. USCAR 30, Performance Specification for Automotive Universal Serial Bus (USB) Connection System.

14. USCAR 37, High Voltage Connector Performance Supplement to SAE/USCAR-2, one of the most commonly used standards for high voltage connectors.

15. USCAR 38, Performance Specification for Ultrasonically Welded Wire Terminations.

16. USCAR 44, Performance Specification for Automotive Wire Harness Retainer Clips.

17. USCAR 45, Performance Specification for Welded Wire-to-Wire Splices.

18. USCAR 49, Performance Specification for Miniature Automotive Coaxial Connectors, commonly used for MINI FAKRA and Ethernet connectors.

3. Test items for USCAR automotive connectors and harnesses

Environmental stress testing. Low temperature, high temperature, temperature change, temperature and humidity cycling, thermal shock, neutral and alternating salt mist, mixed flowing gas, ammonia fuming, chemical solution resistance, dust testing, water testing, water sealing and high pressure water jet.

Electrical performance testing. Temperature rise, current carrying capability, current cycling, derating curves, dielectric strength, insulation resistance, low level contact resistance and voltage drop.

Mechanical performance testing. Terminal to terminal insertion and withdrawal force, terminal to housing insertion force, push-back force and retention force, terminal normal force, connector mating and separation force, CPA and TPA insertion and withdrawal force, and mechanical strength of auxiliary structures.

Mechanical reliability testing. Mating cycles, audible mating confirmation, free drop, tumble drop, ferrule retention force for high voltage connectors, seal retention force, vibration, mechanical shock and combined three-axis testing, fretting corrosion and fretting wear.

Shielding effectiveness. Line injection, tube-in-tube and triaxial methods; transfer impedance and shielding attenuation.

Signal integrity of high speed cables and connectors. Insertion loss, return loss, voltage standing wave ratio, crosstalk, impedance and eye diagram.

Conductor crimp cross-section analysis.