AUTOOL RT120 12V Automotive Relay Tester

Description

The AUTOOL RT120 is a portable automotive relay diagnostic tool developed for testing compatible 12V 4-pin and 5-pin electromechanical relays used in cars, motorcycles and other suitable vehicles.

A faulty relay can cause problems with fuel pumps, cooling fans, horns, lights, air-conditioning systems and other electrical components. The RT120 provides technicians with a quick and convenient way to identify a working or defective relay before replacing components or carrying out more extensive electrical diagnosis.

Fast Automatic Relay Testing

The AUTOOL RT120 simplifies relay inspection by performing the test automatically.

After connecting the tester to a suitable 12V vehicle battery, insert the relay, select either 4-PIN or 5-PIN mode and press the TEST button. The tester repeatedly activates the relay and evaluates its operation.

This quick process helps reduce manual testing time and provides an easy-to-understand result.

Supports 4-Pin and 5-Pin Relays

A dedicated selector switch allows the technician to choose between:

4-pin relay testing
5-pin relay testing

This makes the RT120 suitable for checking many commonly used 12V automotive and motorcycle relays.

Relay terminal layout and electrical specifications can vary. Always confirm compatibility before inserting a relay into the tester.

Clear LED and Audible Results

The tester communicates the result through simple visual indicators:

Green indicator: The tested relay has passed
Red indicator with warning sound: The relay has failed or is operating abnormally

The straightforward display allows technicians to understand the result without complicated calculations or manual meter readings.

Repeated Testing for Reliable Diagnosis

During operation, the RT120 performs 10 repeated relay closing tests. This helps identify relays that may operate inconsistently instead of checking the relay through only one switching cycle.

The unit is designed to evaluate relay response, repeated operation and consistency during the automatic testing sequence.

Powered Directly by a 12V Vehicle Battery

The tester operates directly from a compatible 12V automotive battery and does not require a separate rechargeable battery.

Its insulated positive and negative clips are attached to the vehicle battery terminals:

Red clip connects to positive
Black clip connects to negative

The approximately one-metre power lead provides convenient access around the engine compartment or workshop bench.

Simple Operating Procedure

Confirm that the battery voltage is within the supported 11V–15V range.
Connect the red clip to the positive battery terminal.
Connect the black clip to the negative battery terminal.
Select 4-PIN or 5-PIN mode according to the relay.
Insert the compatible relay firmly into the appropriate test socket.
Press POWER to switch on the tester.
Press TEST to begin the automatic testing sequence.
Check the green or red result indicator.
Switch off the tester after completing the test.
Key Features

Tests compatible 12V automotive relays
Supports both 4-pin and 5-pin relays
Automatic relay operating test
Performs 10 repeated closing cycles
Checks relay operating consistency
Green LED indicates a passed test
Red LED and audible warning indicate failure
Simple 4-pin and 5-pin mode selector
One-button automatic testing
Insulated positive and negative battery clips
Approximately one-metre power cable
Compact handheld construction
No internal battery or charging required
Suitable for cars and motorcycles
Useful for workshops and mobile technicians

Technical Specifications

Specification	Details
Brand	AUTOOL
Model	RT120
Product type	Automotive relay tester
Supported relay types	Compatible 4-pin and 5-pin relays
Vehicle electrical system	12V
Supported input-voltage range	11V–15V
Working power supply	DC 12V / 1A
Automatic test cycles	10 closing cycles
Test-result indication	Green and red LEDs
Failure warning	Red indicator and audible alarm
Power connection	Insulated battery clips
Cable length	Approximately 1 metre
Working temperature	-20°C to 60°C
Suitable applications	Cars, motorcycles and compatible 12V systems

Suitable For

The AUTOOL RT120 is suitable for:

Automotive electricians
Motorcycle technicians
Vehicle repair workshops
Car maintenance centres
Mobile mechanics
Electrical diagnostic specialists
Automotive training centres
DIY vehicle owners

Common Relay Applications

Compatible automotive relays may control systems such as:

Fuel pumps
Radiator cooling fans
Horns
Headlights and auxiliary lights
Air-conditioning components
Starter-control circuits
Defoggers
Electric accessories

The RT120 tests the relay itself; it does not diagnose the complete vehicle circuit, wiring harness or control module.

Important Compatibility Notice

The AUTOOL RT120 is intended for compatible 12V electromechanical 4-pin and 5-pin automotive relays. It is not intended for 24V vehicle systems unless the manufacturer specifically states otherwise.

Relays with unusual terminal layouts, integrated electronic components, solid-state construction, diodes, resistors or non-standard electrical characteristics may not be compatible.

Always:

Confirm the relay voltage and terminal arrangement
Observe correct battery polarity
Keep the clips from touching each other
Avoid testing damaged or heavily corroded relays
Disconnect the tester after use
Follow appropriate automotive electrical-safety procedures

A relay passing the test does not confirm that the vehicle wiring, fuse, switch, socket, control module or connected component is functioning correctly.