Trailer compliance checks require a reliable power supply to avoid false fault reports, says John Hope, Managing Director at Hope Technical Developments.
Trailer compliance – top tips
1. Lights
LED bulbs are less prone to in- service damage than filament bulbs, but LEDs will fail if they are inserted wrongly – polarity can vary. ?
2. Electrical/air connection box.
Previously fixed in the centre of the trailer bulkhead, many trailers now have a swivelling box that slides from side to side. It provides a more reliable connection for the seven-pin EBS line, reduces the risk of damage to suzie cables and is safer for drivers. However, the extra movement means anything from the bulkhead box to the wiring circuit can become lose, so technicians should check they remain intact, whatever position the bulkhead connection box is in.
Trailers may be less sophisticated than tractor units, but that doesn’t necessarily make carrying out safety compliance checks more straightforward. An electrical and air supply is needed and while this is not a problem in the workshop, trailers are not necessarily at their home workshop when a safety inspection is due.
The Hope Scrutineer has been in service for over 30 years; recognised throughout the industry as an invaluable tool for carrying out fast and reliable safety inspections of trailer electrical and air systems. It helps technicians to quickly pinpoint any compliance issues, allowing the trailer to be returned to service with the minimum of downtime.
With many compliance inspections now being done by mobile technicians, Hope has engineered a mobile version of the Scrutineer that can be installed in the back of a service van. The company has paid special attention to ensuring the machine has a reliable electrical supply.
Each Scrutineer has its own integral air and electrical power connectors. In the workshop, it operates from a standard 28V DC current supply, plus a compressed air feed for air brake system checks.
This reliable voltage supply is essential for accurate test results. Voltage fluctuations can result in the Scrutineer recording a low voltage reading – but low voltage is also a key indication of a potential fault with the EBS system. Power spikes also risk damaging the electronics of the EBS systems.
For mobile Scrutineers, the company recommends operators also install a supplementary battery and a power inverter to enable steady 28V DC power. This will ensure the Scrutineer will have a reliable DC electrical supply for several hours and the volts will remain steady. The inverter can also power to an on-board compressor for air system checks and a voltage protector retains sufficient power remains in the vehicle battery to ensure it starts.
Compliance checks
The Scrutineer is a versatile machine; able to check numerous systems. The machine is hooked up to the electrical and air connectors on the front of the trailer, the technician can then proceed to the back of the trailer and use the remote control to carry out function checks – there’s no need to involve a second person to activate light switches and so on.
On the electrical front, lighting circuits, ABS and EBS operation and supply circuits can all be quickly confirmed as compliant. Technicians can check air valve operations are at the correct settings and pressure, the EBS CAN line integrity, the operation of brake mechanisms and operate the brakes via a remote control.
Light circuits can be checked by socket PIN number, allowing incorrect wiring to be spotted and corrected. ABS/EBS system checks are done via 24N, 24S and the ISO- 7638 connections. It’s easy to perform a quick visual check of how many bulbs are in operation on a circuit with the integrated bulb meter and identify any earth faults immediately.
A clever auto cycle feature allows the operator to carry out a full lighting circuit check; with the push of one button, the Mobile Scrutineer will automatically cycle through all of the lights on the trailer.
