In the electronic control function of the car dashboard printed circuit board assembly, the main control circuit adopts the single-chip microprocessor as the control unit. After the signal input circuit inputs the collected signal to the microprocessor, it is processed by the software in the microprocessor and then output to the microcomputer. The LCD drive circuit of the processor output port and the meter head motor drive circuit. The advantage of this is that it adopts a unified stepping motor structure, which is centrally controlled by MCU, with high working accuracy, strong function and versatility, high reliability, and effective cost reduction. In addition, it also makes the alarm function more intelligent. When the speed value exceeds the set limit value, the LED indicator light will light up to automatically remind the driver to perform the corresponding operation, which better guarantees the safety during driving.