If you want a more in-depth analysis, someone is going to have to look at it, take measurements, make observations, or do some tests that provide some information. If you don't know how to do any electrical testing, something you can start with is checking the copper nuts on the two larger terminals on the solenoid. They often work loose. Be careful with the wrench because one of those terminals is tied right to the battery and if the wrench touches that terminal and anything metal on the car body at the same time you'll have huge sparks, a potential for the battery to explode from the hydrogen gas they give off, and the wrench can melt. I used to call it "common sense", but it isn't common knowledge among people who don't work on cars every day.