What does continuity testing assess, and what is an acceptable result for a wiring harness?

• A. Continuity testing measures insulation resistance.
• B. Continuity testing checks for an unbroken path; acceptable readings are a low resistance value.
• C. It tests for cross-talk.
• D. It verifies amperage capacity of the wire.

Answer: (B)

Continuity testing checks for an unbroken electrical path between two points. In a wiring harness, you’re verifying that each conductor runs from end to end without a break, so the current can flow freely.

The best result is a low resistance value, ideally near zero ohms for a single, intact conductor. A reading that’s high or infinite means there’s an open somewhere in the path, indicating a break. The exact “acceptable” low value can vary with wire length and gauge, but it should be much lower than an open-circuit reading.

Perform the test with power off and across the conductor’s two ends (or through the harness connector) to avoid misleading results from energized circuits. This test specifically confirms a continuous path, unlike insulation resistance testing (which checks for leaks in insulation) or measurements of cross-talk or amperage capacity.