Hi, I am a professional certified mechanic, with an engineering background, and 35+ years experience. I will do my best to assist you. Also keep in mind I don't know if you are a pro or a novice, so feel free to add any additional info at any time.
What you have to do is check the compressor for power when it the compressor wont come on. Sometimes the compressor clutch will go bad and not come on when the electrical system sends power to it, to turn it on. If the compressor isn’t getting power when it wont come on, the compressor and clutch are good. If the compressor is getting power but not coming on, I would have the compressor clutch replaced, it would be all you need, you don’t have to change the whole compressor.
Beyond that if the compressor isn’t getting power when it wont turn on check the connection at fuse no 5 a 15amp fuse in relay center under the hood. From there you need to have the AC compressor control relay checked in center back of the engine compartment, if it is going bad it can cause the problem you are having. There is a pressure sensor that can fail and cause the symptoms you are having so that is another possibility too. Odds are the computer isn’t at fault. One last thing is it pays to have an electrical specialist work on electrical problems like this, they can more easily pinpoint the problem, and will know a lot more about the workings of the electrical system. Go over all of this and if you have any more questions at all, I am here to help. Good luck with it, have a great day, and Thanks for using Just Answer.
I do not get paid for my work unless you rate at 3 to 5 Smiley Faces or Stars, a bonus is always greatly appreciated. If the answer is not clear, let me know what additional help you need, and I will be happy to assist you further.