2013-02 ABS Bulletin - Electric Vehicle (EV) power units

Inspection Bulletin 2013-02 Antilock Brake Systems Inspections. The paragraph on Full-time power units needs to be updated in the ABS Inspection Bulletin. At the time the ABS Bulletin was written, full-time power was thought to be only installed on those power units that are pulling trailers that required have full-time power. Since that time, it has been discovered that full-time power may be found on any power unit, not just those towing trailers that need it. Electric Vehicle (EV) power units also provide full-time power and guidance to inspectors on the inspection of ABS on these vehicles is important as the industry sees increased usage of EV vehicles.

Wording needs to be cleared up so that inspectors know that they may find full-time power on any power unit, including EV vehicles.

Edit the paragraph in the ABS bulletin on Full-time Power Units to read as follows: Full-Time Electrical Power Tractors Most ABS equipped power units energize the continuous power circuit for towed vehicle ABS when the ignition switch is turned on; however, in some applications the circuit is energized even when the ignition switch is in the off position. Full-time electrical power is needed on power units towing trailers in operations needing full-time power to the trailer but may be found on any power unit, including Electric Vehicle (EV) power units. Examples needing full-time electrical power include tank haulers with overflow safety monitoring systems and DOD munitions haulers with mandatory GPS trailer tracking. In such cases, the external ABS malfunction lamps on the towed units will not cycle with the ignition switch or even with the brake pedal. It will be necessary to ask the driver to disconnect and then reconnect the seven-way electrical connector while you observe the ABS malfunction indicators located on the towed units. In addition, the trailer ABS malfunction lamp on the power unit dashboard may only cycle when the seven-way electrical connector is plugged in. Therefore, when performing this procedure for the towed vehicle’s ABS, the trailer ABS malfunction lamp on the power unit dashboard may need to be inspected in the same manor based on the manufacturer of the power unit.