Auxiliary HVAC Systems Technical: Air Conditioning Specialist Module 3/6   With the advancements of technology in comfort systems, auxiliary HVAC systems are becoming common place in today’s vehicles. This course will deal with the description, operation and testing of various auxiliary HVAC systems for different manufactures. Electronic and manual control systems will be covered along with their associated sensors and control modules. Also included in this course will be the repair of rear A/C lines Vs replacing lines due to the cost and complex routing of them on some vehicles.