What tool is essential for testing electrical continuity in circuits?

An ohmmeter is essential for testing electrical continuity in circuits because it measures the resistance of a circuit and determines whether a current can flow through it. When using an ohmmeter, you can check for open circuits or short circuits by measuring the resistance. A low resistance value indicates continuity, meaning that electricity can flow freely, while an infinite resistance value shows an open circuit, indicating no continuity.

In the context of testing electrical systems in trucks and coaches, continuity is vital to ensure that all components, such as switches, wiring, and connectors, are functioning correctly and that there are no breaks or faults in the circuit. Thus, the use of an ohmmeter is standard practice in diagnostics and maintenance to ensure the reliability and safety of the vehicle's electrical systems.