Autool RT120 12V Automotive Relay Tester – 4-Pin & 5-Pin Relay Diagnostic Tool

Autool RT120:

The Autool RT120 Relay Tester is a compact and efficient diagnostic tool designed to quickly test the condition of automotive relays. Relays are essential components used in vehicle electrical systems such as fuel pumps, starter motors, cooling fans, lighting circuits, and air-conditioning systems. When a relay fails, it can cause electrical components to malfunction or stop working completely.

The RT120 allows technicians to easily verify whether a relay is operating correctly without complicated diagnostic procedures. With automatic testing and clear LED indicators, mechanics can identify faulty relays within seconds, saving time and preventing unnecessary replacement of good parts.

Key Features

Fast and Accurate Relay Testing

The device automatically checks the relay’s coil activation, contact switching, and operational consistency to determine whether the relay is functioning properly. This allows technicians to diagnose electrical faults quickly and efficiently.

Supports 4-Pin and 5-Pin Relays

The RT120 is compatible with the most common automotive relay configurations. Simply select the correct mode and insert the relay for testing.

Automatic Test Cycle

Once the relay is inserted and the test button is pressed, the tester performs a series of automatic switching tests to analyze relay performance and reliability.

Clear LED Result Indicators

The tester uses a two-color LED system to display results instantly:

• Green light – Relay is functioning normally

• Red light – Relay is faulty and should be replaced

Simple Plug-and-Play Operation

Operation is extremely easy. Connect the tester to a 12V vehicle battery, insert the relay, select the appropriate mode, and press the test button.

Portable Workshop Tool

The compact handheld design makes it perfect for automotive workshops, electricians, mobile mechanics, and DIY enthusiasts who need a quick and reliable relay diagnostic solution.

Applications

The RT120 is commonly used to diagnose relay issues in:

• Starter systems

• Fuel pump circuits

• Cooling fan relays

• Lighting systems

• Air conditioning relays

• Horn circuits

• Other automotive electrical components

Technical Specifications

• Operating Voltage: DC 12V

• Supported Relay Types: 4-pin and 5-pin automotive relays

• Power Source: Vehicle battery or 12V DC supply

• Indicators: LED pass/fail display

• Operating Temperature: −20°C to 60°C

• Dimensions: Approx. 150 × 85 × 35 mm

• Weight: Approx. 250 g

How It Works

1. Connect the tester’s red and black clips to the vehicle battery terminals.

2. Select the relay type (4-pin or 5-pin).

3. Insert the relay into the test slot.

4. Press the TEST button.

5. The device performs automatic switching cycles and displays the result using LED indicators.

Why Choose the Autool RT120

• Detect relay faults in seconds

• Reduce unnecessary parts replacement

• Improve electrical diagnostic accuracy

• Save time in professional workshops

The RT120 Relay Tester is an essential diagnostic tool for any mechanic or automotive electrician working with vehicle electrical systems.