My 1998 Ford Ranger Extend Stepside 4X4 4.0L won't start!

Check battery voltage, should be 12.4vdc, minimum. If battery is good and still won't turn over, check all battery cables for corrosion and make sure they're tight. If all cables are ok, check for voltage at the starter solenoid small terminal. If voltage is present and still no crank, replace starter

Sounds like a weak battery. You probably need a new one. Have it tested.

We replaced the battery cables & the battery is charged.

Then proceed to next step, check voltage signal at the starter solenoid. Be careful do not assume battery is good just because you changed it, check for proper voltage. 90% of the time the problem is the battery, dirty, corroded or loose battery cables

Have the starter checked,

Try turning the engine over by hand or with a breaker bar on crank, should turn over make sure engine not locked up, then proceed to check solenoid and starter

My 97 Ranger had to have the battery replaced. Then when I got home and got ready for work all power was lost. The cables had to be cleaned again. The auto parts store said my alternator was good. I took it to my mechanic and the alternator was bad. $300 in one week to fix it