If the engine won’t crank, you first need to verify if it’s turning over. If the engine won’t even spin, then verify that the battery cables are tight and clean. If they are not clean, use baking soda and a wire brush to clean the posts off. If the cables are good, confirm that the battery is holding a charge. You can have this checked at an auto store unless you have a load tester. Volt meters can mislead you by showing a 12+ volt reading, until the key is turned. Replace the battery if it will not hold a charge. If the battery holds a charge but still dies after starting and stopping a few times, then the alternator could be at fault. A quick test for most alternators is to take a screwdriver and carefully touch the back center of the alternator. If you touch this shaft when the car is running, it will be magnetic and the screwdriver should stick to it very well.

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If the battery was good but the engine won’t turn the starter may be at fault. The starter has a solenoid which actuates it to engage. Many times you can tap on the solenoid to make it work. If the solenoid is really bad, you can use a screwdriver to “jump” the solenoid across it’s terminals. This jumps the voltage directly to the starter post. It will spark when jumped but the engine should spin over and try to start. If it still won’t spin, the starter itself is probably bad. The starter is located close between the engine flywheel and the transmission input side. If the engine doesn’t want to start, you will have to check that the engine is getting fuel and spark.