According to Johnson, "Using Schematics To Troubleshoot HVAC/R Electrical Circuits, Part 1" came about because of feedback from the industry. "It’s shorter than our fundamentals training videos, and ...

Rule 1: Read first to learn how the circuit works, then redraw to troubleshoot. Rule 2: When tracing a circuit, always work from the load to the battery, or from negative to positive. Rule 3: There is ...