Triple ISO Tester

Advanced circuit tester for testing
your truck’s ISO 7638 Socket,
Trailer Susie, and ABS Functions


ISOTester is an advanced diagnostic device for testing a truck’s ISO 7638 socket, trailer Susie lead and ABS functions for short or open circuits. By running a simple series of tests the ISOTester quickly identifies fault details and the location (tractor unit, Susie lead or trailer), which is not always easy to locate.

  • Tests truck’s ISO 7638 socket
  • Tests ISO 7638 Susie lead
  • Tests vehicle’s ABS functions
  • Reveals missing/faulty ABS warning light
  • Quick to setup
  • Easy to interpret LED display
  • Powered by tractor unit’s ISO 7638 socket
  • Durable construction
  • UK designed & manufactured

How the tester works

When you plug the tester in, it will test all the pins against each other for live and earth. The tester is to be powered by all the pins except pin 5. If led 1, 2 or 5 are green it means there is a good live above 19.5 volts, but if they are red it means the live is below 19 volts. If led 3 or 4 are green it means a good earth but if they are red it means a bad earth.

Testing the ISO 7838 Susie Lead

The ISOMASTER is plugged into the trailer end of the Susie lead, while the other end of the Susie lead is connected to the truck as usual. The LEDs indicate the test result as per the key printed on the side of the unit.

Testing the truck's ISO 7638 Socket

The ISOMASTER is plugged into the truck’s ISO 7638 socket and the ignition is switched on. If all 5 LEDs light up green this indicates a pass. If one or more LEDs light up red the fault can be diagnosed using the key printed on the side of the unit.


EBS/ABS Sensor and Exciter Ring Tester

For testing and indentifying sensor, gap and exciter ring faults on any EBS/ABS system.


Lightweight, portable and simple to operate

The SensorMaster is supplied with a 1.6m high quality cable and a separate universal adapter for those applications where the standard lead’s termination is not applicable. The SensorMaster comes ready to use straight out of the box.

The SensorMaster is compatible with 90% of applications as standard. It works with any ABS/EBS system made by Knorr Bremse, Haldex or Wabco fitted to any type of commercial vehicle whether it be truck, trailer, bus or coach.

The SensorMaster tests for the following causes of sensor related faults:

  • Correct OHMS resistance
  • Open Circuit
  • Short Circuit
  • Pole ring tooth damage
  • Pole ring mis-alignment
  • Sensor gap measurement

Potentiometer Tester

This tester is used to check caliper potentiometer readings and to determine the wear status of brake discs and brake pads.

Brake discs and brake pads are some of the most important wearing parts on vehicles. Before replacing them it is worth testing them with an automotive Potentiometer Tester.

To check the potentiometer simply connect the corresponding cable to the brake potentiometer, power the tester and choose which type you are testing. This can be can be carried out with the caliper installed on the vehicle or with the caliper removed.


Trailer Master

Heavy Duty Power


Lightweight, portable and simple to operate

Portable 24 Volt Power Box with auto light test for testing your trailer electrical system. Designed to enable one operator to test the complete trailer lighting system without the need to connect a tractor unit, using the 24N and 24s power sockets, using the 24N and 24S power sockets, and to test the ABS warning lamp function on the trailer using the ISO 7638 socket.

  • Quick to setup
  • Easy to use
  • Rechargeable from mains supply
  • Housed in a durable carry case
  • Portable 24V power box
  • Tests trailer’s lighting system
  • Tests trailer’s EBS/ABS warning light function
  • Tests trailer’s CAN activity
  • Single operator auto test
  • All necessary leads supplied
  • Designed & manufactured in the UK