Why Is It?

Diagnosis is something you have to learn. Most here don't have a clue. Not being mean by say it, just truthful. I'll rephrase that and say many are not knowledgeable. If you don't know how things work or can't figure it out, just throwing random parts at it hopefully will fix the problem. At the dealership or repair shop, you don't have the option to just throw parts at it. The customer won't stand for that.