Pros, I hope things are ok at your.

Hi Pros,
I hope things are ok at your end. I have small question with you. I am a newbie in this field. A few days ago I came up with this customer who had this problem where his cars ac was not working. Turned out his compressor was non functional. I tried to run some diagnostic tests with different sensors. I dont know what I did wrong but suddenly his cars software crashed. I the result of this his car stopped turning on. Can you tell me please what I did wrong