What is Insulation Resistance Testing for wire harnesses??

Generally, insulated wires are used for wire harnesses. In other words, the conductor is covered with an insulator. An insulator does not mean that no current flow at all. A small amount of current flows due to the resistance of the insulator. If there is insulation failure in the processed part of this insulator or harness, more current will flow than normal. The insulation resistance test measures this current and determines the resistance according to Ohm's law.