2004 ford explorer wont start or crank over HELP!!!!!!!!!!!!!!!!!!

Check crankshaft position sensor, it's close to the harmonic balancer. Due to rear and tear, the pulley could dislodge from the harmonic balancer and eat into the sensor. Parts required: harmonic balancer and crankshaft position sensor.

with a helper and test light or volt meter.have helper to turn key to crank position,check the small wire on the starter for signal from switch.there won't be spark if it ain't cranking over!what's the battery testing at,volts?