- Versatile multifunction car circuit tester with an integrated design that simplifies load device testing, voltage testing, pulse signal testing, and identification of short circuits or fuse faults. It also supports bulb loading and displays power polarity. - Versatile circuit testing with three working modes and an option to choose LED digital display or bulb mode, providing computer mode for efficient diagnosis of electrical issues. - Improved testing capability with a top-mounted test bulb to quickly determine wire power failures, reveal invisible poor contacts, and identify phantom voltage faults; it can also perform pure voltage testing and bulb load testing for more accurate results. - Advanced polarity detection with two probes; simplifies load device testing and power polarity display, red light indicating positive and green indicating negative. - Use scenarios: - Inspect car fuse boxes and wiring before installing aftermarket accessories to confirm power availability and polarity. - Diagnose intermittent lighting or accessory power loss by testing voltage, pulse signals, and contact quality. - Verify wiring harness integrity and detect poor connections in a new installation, ensuring proper voltage and polarity before final assembly.