Trailer Tester for Checking Trailer Lighting

Frequently Asked Questions About Trailer Testers and Trailer Lighting Testers

A trailer tester allows you to check a trailer's electrical lighting system independently of the towing vehicle. The following questions explain how the ATA 07 works, which 7- and 13-pin connector systems it supports, and how a trailer tester differs from a towing vehicle tester.

• What is a trailer tester?

  A trailer tester is a testing device used to check the electrical functions of a trailer.

  The ATA 07 simulates a 12-V towing vehicle, including the necessary power supply. This allows the trailer's lighting and electrical connections to be tested without the need for an actual towing vehicle.

  The trailer tester is part of the Test and Diagnostic Equipment for Automotive Electrical Systems product line.

• What can be tested using the ATA 07?

  The ATA 07 is used to test trailer lighting systems and assists in troubleshooting the corresponding electrical circuits.

  Typical applications include, for example:

  • Functional testing of trailer lighting
  • Troubleshooting lighting failures
  • Diagnosing loose connections
  • Identifying ground problems
  • Testing after work on the wiring harness or connectors
  • Preparation for and approval of the annual vehicle inspection (HU)
• Can the trailer lights be tested without a towing vehicle?

  Yes. That is exactly what the ATA 07 was designed for.
  
  The device simulates the operation of a 12-V towing vehicle, including the power supply.
  
  This allows a trailer to be tested directly in the workshop without the need for a passenger car or other towing vehicle.

• Why is it a good idea to take the test without a towing vehicle?

  This allows the trailer and the towing vehicle to be tested independently of each other.

  If the trailer lights function properly with the ATA 07, this can be an important indication during troubleshooting that the cause may lie with the towing vehicle or its trailer socket.

  The towing vehicle's socket can then be tested separately using a towing vehicle tester for trailer sockets.

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

  The two test devices check different aspects of the electrical connection.

  Trailer Tester:
  The trailer tester simulates the towing vehicle and checks the trailer and its lights.

  Towing Vehicle Tester:
  The towing vehicle tester simulates the trailer and checks the trailer socket or the output signals from the towing vehicle.

  This separate testing allows a fault to be more precisely attributed to either the trailer or the towing vehicle.

  You can find suitable devices for testing the towing vehicle under Towing Vehicle Testers for Trailer Sockets.

• What trailer connectors does the ATA 07 support?

  The ATA 07 is designed for the following 12-V connector systems:

  • 13-pin, 12 V (WeSt)
  • 7-pin, 12 V per DIN/ISO 1724
  • 13-pin, 12 V Multicon

  This allows for the testing of various connector systems used in passenger cars and trailers.

• Can a 7-pin trailer plug be tested?

  Yes.
  
  The ATA 07 supports 7-pin 12-V trailer connectors in accordance with DIN/ISO 1724.
  
  This makes the device suitable for trailers with standard 7-pin connectors.

• Can a 13-pin trailer plug be tested?

  Yes.
  
  The ATA 07 supports 13-pin 12-V connector systems (WeSt) as well as 13-pin Multicon systems.
  
  Before testing, you should check which type of connector is installed on the trailer in question.

• Is the ATA 07 suitable for 24-volt truck trailers?

  The ATA 07 currently available is a 12-V tester.

  It is therefore not generally designed for use with 24-V trailer systems.

  For testing commercial vehicle or 24-V systems, a tester specifically designed for that purpose must be used.

• Does the ATA 07 require an external car battery?

  No.

  The ATA 07 has a built-in 12-V battery with a capacity of 1.2 Ah.

  This allows the device to be used on the go without having to be connected to a vehicle battery during the trailer inspection.

• How is the ATA 07's battery monitored?

  The ATA 07 features various LED status indicators.

  These include, among others:

  • Capacity indicator upon startup
  • Warning indicator when battery voltage drops below 10.5 V
  • Current flow indicator
  • “Battery charging” indicator
  • “Battery full” indicator

  This allows you to monitor the device’s operating and charging status.

• Does the ATA 07 turn off automatically?

  Yes.
  
  The tester has an automatic shut-off feature.
  
  If the device is not used for two minutes, it shuts off automatically. This helps conserve the built-in battery.

• Can the ATA 07 be used to detect a ground fault on a trailer?

  The ATA 07 can assist in troubleshooting ground-related issues.

  If one or more lighting functions are not working properly, possible causes may include faulty ground connections, cables, contacts, or lights, among other things.

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

• Can the trailer tester be used to find a loose connection?

  The ATA 07 can assist in troubleshooting sporadic lighting problems and loose connections.
  
  During functional testing, for example, plugs, cables, and connections can be specifically checked or moved to isolate an intermittent fault.

• Can the ATA 07 be used to test the trailer wiring?

  The ATA 07 allows for a functional test of the electrical trailer system.

  If a fault occurs with a specific lighting function, the wiring, connectors, ground connections, and lights can then be examined in detail.

  For direct resistance, voltage, or continuity measurements, suitable multimeters for automotive and commercial vehicle workshops are also used.

• Can the ATA 07 be used to prepare for the HU?

  Yes.

  Leitenberger specifically cites pre-inspection preparation and inspection as typical applications of the ATA 07.

  This allows the lighting functions of a trailer to be checked before the general inspection and any existing faults to be corrected.

• Can the trailer lights be inspected after a repair?

  Yes.

  The ATA 07 is suitable for functional testing after repairs or maintenance, for example, on:

  • trailer lighting
  • wiring harness
  • trailer connector
  • electrical connections

  This allows you to verify proper function before reconnecting the trailer to a towing vehicle.

• Can the ATA 07 also inspect travel trailers or caravans?

  The ATA 07 can generally be used for suitable 12-V trailers with a supported 7- or 13-pin connector system.
  
  The existing connector system and the electrical function to be tested are the determining factors.
  
  Not every additional electrical function of a travel trailer is automatically included in a lighting test.

• Does the ATA 07 test the trailer outlet on the car?

  No.

  The ATA 07 is primarily designed to test the trailer by simulating a towing vehicle.

  If, instead, you need to test the electric trailer receptacle on a passenger car or commercial vehicle, a towing vehicle tester for trailer receptacles is the appropriate testing device.

• Can a multimeter replace a trailer tester?

  A multimeter allows for specific electrical measurements of voltage, resistance, or continuity.

  The ATA 07, on the other hand, has another advantage: It simulates a towing vehicle and supplies the trailer with the 12-V voltage required for functional testing.

  For more complex faults, trailer testers and automotive multimeters and current clamps can therefore complement each other effectively.

• Is the ATA 07 required for CAN bus vehicles?

  The ATA 07 tests the trailer independently of the towing vehicle and, for this purpose, simulates the 12-V power supply itself.
  
  The CAN bus or control unit architecture of an actual towing vehicle is therefore not the primary focus of the basic trailer test conducted with the ATA 07.