Re: 03 Explorer starting issue. please help
The alternator wouldn't charge the battery so the battery would be low on charge. When an alternator goes bad, you can get an idea that it's not charging by starting the car with the headlights on, see if the lights dim while cranking and get bright when you get it started and rev the engine. It still should be checked because if the battery is very good, it will be hard to notice.
If a battery is weak, the lights can still work but a heavy load like a starter won't work. Start with checking the battery. Have you tried to jump start it?