Air filter having a moisture sensor for identifying type of filter and moisture content and method of using filter in a vehicle air conditioning system

A method of operating a vehicle air conditioning system having an air filter and an electric circuit section including a moisture sensor disposed at least one of on the air filter and in close proximity to the air filter, the method comprising the acts of:

• generating a signal from the electric circuit section;
• and
• determining both a moisture loading on the air filter and a type of air filter by way of an electronic device as a function of a magnitude of a signal property of the generated signal.

The method according to 19, further comprising the acts of:

• determining an order of magnitude of a natural frequency of at least one of the moisture sensor and an electric circuit containing the moisture sensor by way of the electronic device;
• and
• determining from the order of magnitude of the natural frequency the type of air filter.