This instrument requires trailers to have operational antilock brake systems (ABS) that meet specific performance, installation and electrical-connector standards, and to signal ABS faults to the towing vehicle. It sets test conditions (speeds, load states, tolerances) and wiring/pin-current requirements for the towing-vehicle connector. Manufacturers, retrofitters and owners of towing/trailer electrical interfaces must fit, wire and test ABS equipment to comply, creating equipment, installation and testing costs and dependencies on a compatible towing-vehicle connector.

1. PERFORMANCE REQUIREMENTS

1.1 The ‘Brake System’ of trailers must comply with the requirements of this ADR including clause 7.5 with the ‘Antilock Systems’ operational and in the event of a failure of the ‘Antilock System’ .

1.2 At speeds exceeding 15 km/h the wheels on the ‘Axle(s)’ specified in clause 2.1 of this APPENDIX must remain unlocked when a ‘Control Signal’ of 1.0 ‘E’ (650 kPa) is suddenly applied from an initial speed of 40 km/h +5 to -1 km/h and from an initial speed of at least 80 km/h on a road surface having approximately uniform surface friction on both sides of the vehicle.

1.2.1 This test is to be performed with the trailer laden to both ‘Lightly Laden Test Mass’ and ‘Maximum Loaded Test Mass’ and using the general test conditions from clause 10 and the particular test conditions from clause 11, amended as regards ‘Control Signal’ amplitude and application rates .

1.2.2 Brief periods of locking of the wheels are allowed, but stability must not be affected.

1.1.3 The operation of an ‘Antilock System’ must not be adversely affected by magnetic or electric fields.

2. INSTALLATION REQUIREMENTS

2.1 An ‘Antilock System’ complying with clause 1 of this APPENDIX must be fitted to:

2.1.1 each ‘Single Axle’;

2.1.2 at least one ‘Axle’ in any ‘Tandem Axle Group’;

2.1.3 at least two ‘Axles’ in any ‘Triaxle Group’ .

3. ANTILOCK SYSTEM - ELECTRICAL SYSTEM.

3.1 ‘Antilock Systems’ must be powered by a 12V electrical supply system, through a connection to the towing vehicle, using a connector conforming to DIN Standard 72570 configured for 12 volt operation.

3.2 The connector must be wired to have the following functions :

3.2.1 For trailers not equipped to tow another trailer:

Pin 1 +ve high current trailer solenoid valve supply

Pin 2 +ve low current trailer electronic unit supply

Pin 3 -ve low current trailer electronic unit supply

Pin 4 -ve high current trailer solenoid valve supply

Pin 5 trailer antilock failure, switched to -ve (eg pin 3 or pin 4) upon fault detection

3.2.2 For trailers equipped to tow another trailer:

Pin 1 +ve high current trailer solenoid valve supply, 30 amps minimum rated capacity

Pin 2 +ve low current trailer electronic unit supply, 4 amps minimum rated capacity

Pin 3 -ve low current trailer electronic unit supply, 6 amps minimum rated capacity

Pin 4 -ve high current trailer solenoid valve supply, 30 amps minimum rated capacity

Pin 5 trailer antilock failure, switched to -ve (eg pin 3 or pin 4) upon fault detection, 2 amps minimum rated capacity

3.3 Any break in the supply of electricity to an ‘Antilock System’ and any electrical failure of an ‘Antilock System’ other than a failure of one or all of the electrical conductors between pins 3, 4 and 5 on the electrical connector and the antilock control module must be signalled to the towing vehicle by connecting Pin 5 on the electrical connector to -ve (ie pin 3 or pin 4).

3.4 Each ‘Antilock System’ must connect pin 5 to -ve (eg pin 3 or pin 4) when initially energised and disconnect pin 5 from -ve after not less than 2 seconds or at the latest when the trailer reaches a speed of 15 km/h and no defect is present.