Towing vehicle tester for testing trailer receptacles

Frequently Asked Questions About Towing Vehicle Testers and Trailer Socket Testers

Tow-vehicle testers allow you to test the electrical trailer socket directly on the vehicle without having to connect an actual trailer. The following questions explain the differences between 7- and 13-pin systems, 12- and 24-volt versions, and CAN-bus-compatible testers.

• What is a trailer tester?

  A tow vehicle tester is a testing device used to check the electrical trailer socket on the towing vehicle.

  The tester simulates a connected trailer and indicates whether the corresponding lighting and output signals are present at the socket as they should be.

  Tow vehicle testers fall under the category of testing and diagnostic equipment for automotive electrical systems.

• What can be tested with a trailer hitch tester?

  Depending on the model, the following functions—among others—can be tested at the trailer socket:

  • Turn signals
  • Brake lights
  • Taillights
  • Rear fog light
  • Reversing light

  Some tow vehicle testers also allow you to simulate light failures or a fully connected trailer.

• Can a trailer outlet be tested without connecting a trailer?

  Yes. This is precisely the key advantage of a tow vehicle tester.
  
  The tester simulates the electrical load and functions of a trailer.
  
  This allows the trailer receptacle on the tow vehicle to be tested directly in the shop without having to provide a trailer.

• What is the difference between a tow vehicle tester and a trailer tester?

  The two devices test different aspects of the connection between the towing vehicle and the trailer.

  Towing Vehicle Tester:
  Simulates the trailer and tests the trailer receptacle on the towing vehicle.

  Trailer Tester:
  Simulates the towing vehicle and tests the trailer and its lighting.

  Leitenberger offers trailer testers for trailer lighting for testing trailers.

• How can you determine whether a problem lies with the trailer or the towing vehicle?

  The trailer and the towing vehicle can be tested separately.

  First, the towing vehicle’s trailer hitch is checked using a towing vehicle tester.

  The trailer itself can then be tested—or tested separately—using a trailer tester for trailer lights.

  This allows the fault to be pinpointed more accurately to one of the two vehicles.

• What types of trailer hitches does Leitenberger offer?

  The current product line includes, among others:

  • ZWT 01: 7-pin, 12 V
  • ZWT 02: 7-pin, 24 V
  • ZWT 20: 13-pin, 12 V
  • ZWT 40: 13-pin, 12 V
  • ZWT 50: 13-pin, 12 V

  Adapters are also available for various 7- and 13-pin 12-V connector systems.

• Can a 7-pin trailer outlet be tested?

  Yes.

  The ZWT 01 is designed for 7-pin 12-V trailer receptacles in accordance with DIN/ISO 1724.

  The ZWT 02 is available for corresponding 24-V systems.

• Can a 13-pin trailer outlet be tested?

  Yes.
  
  For 13-pin 12-V trailer power outlets, Leitenberger offers the ZWT 20, ZWT 40, and ZWT 50, among others.
  
  These devices are designed for use with corresponding 13-pin plug systems on the towing vehicle.

• Can a 24-volt trailer outlet on a commercial vehicle be tested?

  Yes.

  The ZWT 02 is designed for 7-pin 24-V trailer sockets in accordance with DIN/ISO 1185.

  It can be used to test the corresponding electrical functions on 24-V towing vehicles or commercial vehicles.

• Are the trailer testers CAN-bus-compatible?

  Several Leitenberger tow vehicle testers are suitable for modern vehicles equipped with CAN bus or headlight monitoring systems.
  
  For example, the ZWT 01 and ZWT 02 feature integrated load resistors and are specified as CAN bus-compatible.
  
  The ZWT 20, ZWT 40, and ZWT 50 are also designed for use with such modern vehicles.

• Why are load resistors important in a trailer tester?

  Modern vehicles sometimes detect a connected trailer or connected lighting devices based on their electrical load.
  
  Integrated load resistors allow the test device to simulate the corresponding electrical load.
  
  This makes it possible to test functions such as trailer detection or lamp monitoring under conditions that more closely resemble real-world use.

• Can a trailer detection system be tested using a trailer tester?

  With suitable vehicles and towing vehicle testers, the simulation of a connected trailer can be used to verify the vehicle's response or the trailer detection system.
  
  The exact functionality depends on the vehicle, its control system, and the test equipment used.

• Can lamp failures be simulated?

  With certain vehicle testers, yes.
  
  The ZWT 20 and ZWT 40, for example, allow for the simulation of relevant lamp failures.
  
  Depending on the vehicle or monitoring system, the simulated failure can then be displayed in the cockpit.

• What functions can be tested with the ZWT 20?

  The ZWT 20 is designed for 13-pin 12-V trailer sockets.

  Test functions include:

  • Turn signals
  • Brake lights
  • Taillights
  • Reversing lights
  • Rear fog lights

  The device also features built-in load resistors and is compatible with CAN-bus-equipped vehicles.

• What is the advantage of the ZWT 40?

  The ZWT 40 provides comprehensive 13-pin 12-V trailer simulation.
  
  Switches and test lights are integrated into the test case and can be turned on or off individually.
  
  In addition, individual bulb failures can be simulated.

• Can the test be performed from the driver's seat?

  This is possible with the ZWT 20, ZWT 40, and ZWT 50.
  
  The devices come with a connection cable approximately 5 m long.
  
  This allows one person to operate the vehicle's various functions from the driver's seat while simultaneously using the test device.

• Can a trailer outlet be inspected after a trailer hitch retrofit?

  Yes.
  
  Testing after installing a trailer hitch or a new trailer plug is one of the typical uses of a towing vehicle tester.
  
  This allows you to verify that the electrical functions are working properly after installation.

• Can a trailer hitch tester be used when preparing for the annual vehicle inspection?

  Yes.
  
  Testing the functionality of the trailer outlet is one of the typical applications of tow vehicle testers.
  
  This allows electrical faults to be detected and corrected even before a vehicle inspection.

• Can a trailer tester help with loose connections or corrosion?

  Yes.

  If individual functions fail sporadically, the tow vehicle tester can help with systematic troubleshooting.

  Possible causes may include, for example:

  • corroded contacts
  • damaged connectors
  • wiring faults
  • grounding issues
  • problems following repairs in the rear section

  For more in-depth electrical measurements, automotive multimeters, current clamps, and electrical testers can also be used.

• Can a cable break be detected using a cable tester?

  A trailer tester first indicates whether the relevant electrical function is present at the trailer socket.

  This allows you to narrow down the affected circuit.

  To precisely locate a wiring fault or cable break, you can then use appropriate automotive multimeters, current clamps, and electrical testers or automotive test lights and multifunction testers.

• What is the VK 26 adapter?

  The VK 26 is an adapter from:

  a 13-pin 12-V plug conforming to ISO 11446 to a 7-pin 12-V socket.

  This allows a compatible traction vehicle tester to be used with a different connector system.

• What is the VK 27 adapter?

  The VK 27 operates in the opposite direction.

  It connects a 7-pin 12-V plug conforming to DIN/ISO 1724 to a 13-pin 12-V socket conforming to ISO 11446.

  This allows different 7-pin and 13-pin 12-V systems to be combined with the corresponding towing vehicle testers.

• Can the trailer itself be tested using a trailer hitch tester?

  No, or only indirectly via the simulation.

  The towing vehicle tester primarily checks the trailer socket and the output signals of the towing vehicle.

  A trailer tester for checking trailer lighting is intended for directly testing the lighting and electrical system of an actual trailer.

• Can a multimeter replace a tow truck tester?

  Not entirely.
  
  A multimeter can be used to measure individual voltages, resistances, or circuits.
  
  A trailer tester, on the other hand, simulates a connected trailer or the corresponding electrical load, thereby enabling a realistic functional test of several trailer socket functions.
  
  The two devices therefore complement each other for more complex diagnostic tasks.