WHY WONT MY CAR CRANK

The battery is first. Ensure you have a fully charged battery that is able to handle a load. Then check all cable connections and verify they are all clean and secure. Ensure your vehicle transmission gear shift lever is in the "PARK" or "NEUTRAL" position, as your vehicle needs to see this to crank the engine. Testing beyond this would be to check any fuses to see if any are blown, and to do a starter draw test. Usually, though, the concern will appear before this point.