Methods, systems, and devices for determining the integrity of an engine harness are provided. In embodiments, an engine harness tester may include a power source providing an input voltage, a voltage regulator configured to convert an input voltage to an operating voltage, which may be applied to individual circuits that include segments of the engine harness routed through corresponding injectors, and a display for displaying the condition of each segment of the engine harness. In embodiments, the condition of a respective segment may include the condition of the electrical continuity of the individual circuit including the respective individual segment. The display of the engine harness tester may include a plurality of status indicators, each status indicator configured to display the condition of a respective individual segment of the engine harness.