Use only with HELLA LED indicators. If the existing vehicle electrical system is programmed to monitor the lighting even when it is not in operation, this is referred to as a cold check. During a cold check, a small test pulse is transmitted to the lamp while it is switched off to see whether this pulse is discharged via the bulb to ground. The energy here is so low that the bulb does not light up. As LED lamps are essentially not suitable for this form of monitoring, HELLA offers an electronic system for "simulation of the cold check" in order to ensure operation. The simulation device is connected between the central control unit and an ISO 13207-compliant LED direction indicator. The cold check control unit checks the function of the direction indicator during operation using the ISO pulse. If the direction indicator fails, the device saves the last status, which means this can then be displayed during the next cold check.