A harness failure typically results in a system-level failure. While printed circuit board assemblies are manufactured in highly controlled, automated environments, cables and wire harnesses serve as the physical interface to the external environment, subjecting them to dynamic routing, mechanical stress, and varying thermal conditions.

This book defines harness assembly as a controlled engineering discipline rather than a manual craft. It details the material science governing wire selection, vital mechanical parameters required for a reliable crimp, and testing procedures necessary to verify continuity and insulation resistance.

Standardizing these mechanical interfaces systematically eliminates intermittent connectivity issues that complicate final system integration and compromise long-term reliability.