Trailer and Towing Vehicle Tester, 7- and 13-Pin

The tester is designed for checking 12 V electrical connections on trailers and towing vehicles such as passenger cars and motorhomes.

It supports both 7- and 13-pin connections and allows faults in trailer plugs, vehicle sockets and the associated wiring to be identified quickly.

Testing a Trailer Connection

This procedure can be used for trailers, caravans, bicycle carriers and similar equipment:

1. Connect the trailer plug to the corresponding socket on the tester. Use one of the supplied adapters if required.
2. Press the yellow button on the side of the tester.
3. Check the LED indicators. The LED functions correspond to ISO 1724.
4. If all required LEDs illuminate, the wiring is functioning correctly.
5. If an LED does not illuminate, the corresponding cable or circuit is defective.

Pin B on 7-Pin Connections

Depending on the wiring configuration, pin B on a 7-pin socket may be used for either the rear fog light or a permanent 12 V supply.

Take the vehicle and trailer wiring configuration into account when interpreting the test result.

Testing a Car or Motorhome Socket

1. Connect the tester to the 7- or 13-pin socket on the towing vehicle. Use one of the supplied adapters if required.
2. Press the yellow button on the side of the tester.
3. Check the LED indicators. If all required LEDs illuminate, the wiring is functioning correctly.
4. If an LED does not illuminate, check the corresponding output and wiring.

Testing Individual Socket Functions

The individual circuits of the towing-vehicle socket can also be checked separately:

1. Switch on the ignition if required.
2. Activate the left direction indicator.
3. The corresponding LED on the tester must flash at the same frequency. If it does not, the indicator circuit or wiring may be defective.
4. Repeat the test for the right direction indicator, tail lights, brake lights and rear fog light.

An optional 4 m extension cable allows the indicators to be observed from the driver’s seat.

Scope of Delivery

• 1 × trailer and towing vehicle tester
• 1 × adapter from 7-pin to 13-pin
• 1 × adapter from 13-pin to 7-pin

Technical Specifications

• System voltage: 12 V
• Supported connections: 7-pin and 13-pin
• Indication: LED
• LED functions: according to ISO 1724
• Tester power supply: 1 × 9 V block battery
• Battery included: no