Very easy to test starter. If you want to avoid removing it. Which I don’t see why you would because it’s incredibly easy to do so. Take a set of jumper cables. Hook them to the battery and on starter end ground black cable anywhere on starter and as soon as positive touches the big terminal on starter solenoid. The starter should spin. If not the starter needs replaced or rebuilt with new brushes. Easy to do. If the solenoid clicks when turning the key. Solenoid is good and doing it’s job. It’s easier to test starter removed from car. But, You can do it either way. Good chance your battery is no good. Learn how to properly test a car battery. Just because it holds a charge doesn’t mean it’s any good. It might have a dead cell. Easy to test for that too. If the battery voltage dive bombs below 8 to 9 volts after you verified it holding a charge of 12 - 13 volts. The battery would have a dead cell and is no good. This can happen to newer batteries too.
