A diagram of an air conditioning system for a car can be useful for car owners, who may be able to use it in solving some of the basic problems that the system may incur. It can also be useful for mechanics, who, by knowing ahead of time exactly how the system works, can reduce manual labor time, and for students to understand the basics of AC systems.
Diagrams for general AC systems are especially useful for students. These diagrams describe the main components of any system and when accompanied by text, explain how each one works. They are also useful for the do-it-yourself car repairman who wants to try to fix some of the more simple problems in the system without heading to the mechanic or who wants to understand the system without taking classes.
Diagrams for specific models, however, are useful for mechanics. Although all AC systems are similar to one another, some use expansion valves, while others use orifice tubes, and some models might have an accumulator instead of a receiver dryer. Furthermore, the exact positioning of all the components will vary from model to model. Having an accurate diagram can reduce the time spent on diagnosis and repairs.