LED light indicators offer ﬂeet operators a signiﬁcant improvement in reliability over the traditional incandescent bulb and an important costs saving, so LED lights are becoming increasingly more popular. Regulation ECE R48 requires that any failure of the Direction Indicator circuit must be informed to the driver either visibly or by the use of an audible signal. For LED indicators there is an ISO standard (ISO 13207-1) that outlines the required method. However there have been issues in the market, particularly with ﬂeets of articulated vehicles. In many cases, the prime movers ﬂasher unit may not be compatible with the ISO 13207-1 signal output on a trailer ﬁtted with LED light units. This can be overcome by the ﬁtting of a compatible electronic ﬂasher unit. The alternative solution is to effectively make the trailer lighting system universal by ﬁtting the LED Light Link unit. This will allow the trailer to be coupled to any vehicle regardless of the type of ﬂasher unit ﬁtted.