A wire runs behind a damaged door panel from a connector ground terminal to a ground bolt. To check continuity between the ground terminal and the ground bolt, use a:

• A. DVOM to check the voltage drop while operating the door lock
• B. ohmmeter with the door panel disassembled
• C. light tester
• D. in-circuit resistance measurement under no-load

Answer: (A)

When you’re checking a ground path that must carry current, you want to see how it behaves under real operating conditions rather than just a static check. A digital volt-ohm meter is used to perform a voltage-drop test across the ground path while the door lock is operating. By measuring the voltage difference between the ground terminal and the chassis ground (ground bolt) while the lock is drawing current, you can detect how much resistance exists in the ground return. A small drop means the ground path is solid; a large drop points to a poor connection, corrosion, or a damaged wire that needs attention. This approach reveals the actual performance of the ground under load, which is what matters for reliable operation.

An ohmmeter would test continuity only with power removed and while the circuit is isolated, which doesn’t reflect how the ground behaves when current is flowing. A light tester isn’t precise enough to quantify the voltage drop and won’t pinpoint the resistance issue. In-circuit resistance measurements under no-load can be misleading due to other components and parallel paths influencing the reading.