In modern trailers, manufacturers increasingly equip the lighting system with Light Emitting Diodes (LEDs). As opposed to conventional light bulbs, LEDs are semiconductor components. In case of a lamp failure, the usage of LEDs may therefore result in a malfunction of the statutorily required failure indicator. When using a light bulb, the function of the failure indicator is based on an interruption of the galvanic connection between operating voltage and ground. Due to its characteristics as a semiconductor, a Light Emitting Diode disables a galvanic connection (UF ~0.7 V). In case of the failure of one diode, the defect is not indicated because of the multiple interconnected design of an LED-lamp. Thus, the functionality of the failure indicator cannot be guaranteed to comply with the statutory requirements.

On request, ERICH JAEGER offers a CAN-based trailer control module for modern vehicles which enables the electronic detection of light bulbs as well as LED-lamps. This detection ensures that, in case of a lamp failure, the respective signals are transferred to the supply system via the CAN bus thus guaranteeing the functionality of the failure indicator to comply with the statutory requirements.