I was not a technical person. I was an IAS aspirant interested in mathematics who studied Botany and ended up repairing air-conditioners and refrigerators!!
My friend often used to educate me in the technical aspects of the business.
He will question me:
Refrigerator is not cooling properly....
I will say:
(1) The plug top is to be removed and incoming current checked. There may not be any supply.
He: Supply is there
(2) We have to check the compressor.
He: Compressor is okay.
(3) Gas (refrigerant) might have leaked out of the system.
He: No. There is sufficient gas in the system.
(4) The relay might have burnt.
He: Relay is in good condition.
(5) Ah! Thermostat..
He: Thermostat is okay.
(6) There must be door leakage.
He: No leakage in door.
Any suggestions? Please give suggestion in comments section.