Digital circuit tester, automotive light, voltage detector pen, real-time LED display, 5V-30V range, fuse and fault detector for car, truck, DIY

[Real-Time Voltage Display]: Equipped with an LED screen that clearly displays live voltage from 5V to 30V, allowing you to instantly monitor battery performance and circuit status, even in dark garages. The integrated rear probe light provides enhanced visibility during nighttime repairs. Automatic Polarity Identification: Quickly distinguishes between positive and negative terminals using intuitive LED color prompts, where red indicates positive signals and green indicates negative, helping you avoid connection errors when testing fuses, sensors, or complex wiring harnesses without guesswork. [Comprehensive Circuit Diagnostics]: Detects a wide range of automotive issues, including blown fuses, short circuits, virtual electricity, and poor grounding, while testing critical systems such as ABS, speed sensors, ignition circuits, and fuel injection modules to pinpoint faults. [Advanced Frequency Prediction]: Measures AC signals in the 5V to 30V range to estimate injector pulse frequency, spark timing, and crankshaft sensor outputs, providing professional-grade data analysis capabilities that help effectively diagnose intermittent engine problems. Versatile Three-Mode Operation: Features three distinct operating modes easily switched via a single body button to suit different testing scenarios such as Hall sensor checks, LAN circuit detection, or exhaust gas recirculation analysis for vehicle electrical system coverage.