Why does an air conditioning repair man need technical drawing?
He better understand the technologies behind air conditioning and the technologies of the equipment needed to work on air conditioners or he will not be able to properly find problems and fix them.
To be a auto repair person, you need to have a strong understanding of our an automobile engine works, from either experience or education. In addition to developing technical skills, a good auto repair person should have critial and analytical thinking skills to solve problems that are not immediately obvious. www.cartalk.com
I have to assume that your question was entered wrong. If you are asking how to recharge the air conditioning on a 1986 International Harvester then that would make sense. The answer would be to have a repair facility do it as it came with R12 and would have to be changed over to R134A. This is not something you need to be doing.