DEVICE FOR DETECTING A FILTER LOADING

A filter device of an air-conditioning system of a motor vehicle is provided. The filter device has at least one indicator device arranged in the filter device, the indicator device having at least one electrically conductive indicator material, the conductive characteristics of which vary in a manner dependent on the degree of loading of the filter device with filtered particles. Also provided is a motor vehicle having an air-conditioning system comprising the filter device, and a method for detecting the state of the filter device.