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RS PRO Electrical Tester

28 In stock - FREE next working day delivery available
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RS PRO Automotive Relay Tester

Introducing the RS PRO Automotive Relay Tester, also known as the Relay Buddy. It’s a high-quality device that can quickly give an indication of the general health and functioning of the most common relays often found within the automotive industry. It can be used to perform the following tests: coil resistance, surge suppression device (resistor or diode), open/closed contact integrity, contact cyclic testing for intermittent failure detection, loaded contact continuity, relay contacts stuck open or closed and time to contact closure and opening. It’s an essential piece of test and measurement equipment for those working in industries and applications where there is a high reliance on relays functioning at their optimum performance rate.

Features and Benefits:

  • This RS PRO relay tester can quickly and accurately test electro-mechanical relays normally found in vehicles and is ideal for use within the automotive industry

  • The unit can quickly and easily identify and indicate the test results with a series of red, green and yellow LED performance lights, visually letting the user know the status of the test

  • It is suitable for various checks including relay coil resistance/relay contacts/cyclic testing

  • This device allows for quick and easy off the car relay testing and is an ideal diagnostic tool for any technician or automotive electrician

  • 20 to 50 ohms Coil Resistance (includes any parallel transient suppression resistors)

  • 9 V Coil Test Voltage

  • 200 Milliohms Contact Resistance Threshold


Relay testers are devices that are used to check the power of relays that are found within a wide range of applications. They are easy to use devices that can quickly test and identify an unknown relay terminal configuration, while self-configuring it’s own internal circuitry to adapt and perform all the required tests, automatically. It can be used in a range of industries like:

  • Automotive

  • Heavy-duty machinery

  • Marine

  • RV equipment

How does the relay tester work?

The device will check the control side of the relay by applying a signal to the relay coil, while doing this, it will check for the proper functioning of the relay contacts. By using this relay tester, it operates the relay several times during each test session to get consistency in every test cycle. It will fail the relay and light up the LED light to let the user know that the cycle was unsuccessful during the test session.


RS PRO is our own brand range and brings you a wide range of high-quality, great value products offering you more choice. Trusted by engineers all over the world, every part of every RS PRO product has been rigorously tested against demanding industry standards; they’re only given the RS PRO seal of approval if we’re confident of their exceptional quality, which means you can be confident too.


  • The relay tester is unable to test the relay contacts under every different load scenario that your relay may encounter

  • A voltage drop check across the closed contacts while in the live circuit is advisable

Test TypeAuto Test
Battery Type9 V
Dimensions128 x 68 x 30mm
Power SourceBattery