Working Principle

The AUTOOL BT250 Electrical System Tester uses electromagnetic induction to check voltage signals. When the device’s metal probe contacts a circuit, its built-in highly sensitive sensing component detects the alternating magnetic field around the circuit. If current is flowing through the circuit, the LED indicator on the device immediately lights up, providing you with an intuitive and accurate display of the electrode’s properties.

Features

Professional Circuit Tester: Powered by the car’s battery or cigarette lighter, no additional batteries or cables are required. In addition to testing circuits related to components, it can also serve as a temporary power source for testing vehicle components like radiator fans, starter motors, relays, window regulators, and windshield wipers.

Wide Vehicle Compatibility: Voltage test range of 0-65V, supports testing for various types of vehicles, including cars, motorcycles, trucks, excavators, ships, RVs, and more.

Multiple Application Functions: The circuit tester features four testing modes, allowing for flexible switching between DC voltage testing, AC voltage testing, resistance testing, and diode testing. It supports polarity identification, continuity testing, signal circuit testing, ground fault testing, circuit tracing and locating, jumper wire detection, and activation of components.

Easily Locate Faults: The BT250 allows you to easily identify issues such as circuit breaks, open or closed circuits, and short circuits. It helps test vehicle switches, relays, headlights, taillights, faulty sockets, diodes, fuses, wires, and the continuity of electrical circuits.

Automatic Short Circuit Protection: The circuit finder comes with short circuit protection. If an overload or short circuit occurs, the device will automatically restart to protect both the device and the vehicle.

DC Voltage Testing: With a resolution of up to 0.1V and an accuracy of ±0.2V, it precisely measures the voltage values at various points in the vehicle’s electrical circuits.

AC Voltage Testing: Capable of detecting the maximum and minimum voltage values of the tested circuit, as well as the power frequency and duty cycle.

Resistance Testing: Resistance range from 0 to 200kΩ, allows for measuring the resistance between the probe and the auxiliary ground wire of the tested circuit.

Diode Testing: Quickly tests the operational status of diode components and accurately checks for open circuits and continuity issues.

Backlit HD Color Display: Equipped with a 1.7-inch color screen that ensures clear visibility of test data, even in bright or dim environments.

Multiple Language Options: Chinese, English, Russian, German, Portuguese, French, Italian, Spanish, and Polish.

Operating Instructions

Note: Upon initial use of the device, the buzzer will emit a “beep” sound, and the LED light will automatically turn on. You can toggle the light and buzzer on or off based on your actual needs. Before testing a circuit or component for the first time, please perform a self-check to ensure the circuit tester is in proper working condition.

Self-Check Procedure：

1. Connect the red clamp to the positive terminal of the car battery and the black clamp to the negative terminal.

2. Short press the mode button to select DC voltage mode.

3. Touch the tip of the circuit tester probe to a contact point with an unknown polarity.

4. If the LED and screen on the circuit tester light up red and display a voltage value, it indicates that the contact point is positive voltage.

5. If the LED and screen on the circuit tester light up green and display a voltage value, it indicates that the contact point is negative voltage.

Continuity Testing：