Stepper Motor Failure Due to Power and Grounding Issues

Verify the power delivery path by measuring the voltage at the VMOT and GND terminals of the driver using a multimeter; it must match the motor's required voltage (typically 12V–24V). Confirm that the Ground (GND) of the external power supply is physically connected to the GND pin of the Raspberry Pi. Failure to establish a common ground prevents the Pi's logic signals from being accurately referenced by the driver, resulting in a total lack of motor response.