Self Study Program 208 – Air Conditioner in the Motor Vehicle Fundamentals

VAG SSP 208.  In this Self-Study Programme, you will familiarise yourself with the basic purpose and design of an air conditioner. You will learn the functions of the component parts in the refrigeration process, the special characteristics of the refrigerant and why air conditioners require special service specifications.

Air conditioning systems have long ceased to be regarded as luxury equipment. Air conditioners have become a factor in active safety, and today can almost be considered as an integral part of a vehicle’s safety specification.

10 years ago, only about 10 percent of all newly registered vehicles were fitted with an air conditioning system. By 1996, air conditioners were being installed as standard in more than one in four newly registered vehicles.

Customer demand for air conditioning is rising continually.

The design of the refrigerant circuit of an air conditioner is identical in all vehicles. Air conditioner refrigerant circuits only vary in respect of how they are adapted to meet refrigeration requirements.

The component parts shown in the following SSP are common to most air conditioners.

Please note that the figures specified
are given by way of example only.
Depending on refrigeration requirements, the absolute values vary from vehicle to vehicle.


  • The in-car climate
    • Why air conditioning?
  • The physics of the cooling system
    • Applied physics
  • The refrigerant
  • The cooling system
    • The principle of the refrigerant circuit
    • Refrigerant circuit with expansion valve
    • The compressor
    • The mode of operation of the compressor
    • Magnetic clutch
    • The condenser
    • The fluid container and drier
    • Expansion valve
    • Expansion valve Ð new generation
    • The evaporator
    • Refrigerant circuit with restrictor
    • The restrictor
    • The collecting tank
  • System control
    • Components of the safety system
  • Cooling fan circuit
    • Fan circuit for engine/condenser cooling
    • Radiator fan control unit J293
  • Temperature control
    • Manual control
    • Automatic control
    • System overview
    • Control unit with operating and display unit
    • The main temperature sensors
    • Auxiliary signals for temperature control
    • Positioning motor
    • Air ducting
    • Air distribution
    • Air recirculation mode
  • Technical service
    • Safety precautions
    • General information on function influencing factors
    • Fault diagnosis through pressure testing
    • Fault diagnosis through self-diagnosis
  • Information
    • Key cooling system terminology

The Self-Study Programme is not a Workshop Manual.
Please refer to the Service Literature for all the relevant maintenance and repair instructions.

Language: English
Format: PDF
Pages: 76

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