2001 Ranger 3L v6 auto, 186k miles. Never had a problem. One day last month I park it at home. 10 minutes later I need to make a quick trip . Get in, turn key, absolutely nothing happens. Replaced the battery, starter/solenoid, and ignition switch (not the key cylinder lock, but the white box inside the dash below and to the left of the steering wheel...has lots of wires going into and out of it,...turning the key slides a little metal pin inside it up and down). All fuses and relays are good, neutral safety switch is good. Key lock cylinder is mechanically working properly. Engine is not headlights, interior lights, wipers, radio, etc all work fine. Theft light is not blinking rapidly. Headlights do not dim when ignition key is turned. Where do I go from here?

 

Welcome to FTE.
You've done some good trouble shooting & posted up a good list of clues.
From your listing & tests it seems we can assume the battery & its cables & their connections are ok.
SO, at KOEO, do the dash warning lights come on & go through their self checks before turning off??? If not, put the under hood power distribution box located computer power relay on your suspect list. Try giving it a thump, or wiggle & see if it'll wake up. If no joy, try swapping it with a like known good one not needed to run the engine, say the A/C power relay & let us know how it goes.
EDIT: If the warning lights come on & go through their self test indicating the computer is getting power & waking up & seeing as how I see it has a auto tranny, try starting it in "N", instead of "P" & see if the engine will crank. If not, try wiggling the shifter in N or P, while holding the key in the Start position & see if it'll wake up & crank & let us know how it goes.

 

Jeff T:All fuses and relays are good, neutral safety switch is good. Key lock cylinder is mechanically working properly. Engine is not headlights, interior lights, wipers, radio, etc all work fine. Theft light is not blinking rapidly. Headlights do not dim when ignition key is turned.

From that description, it seems the only thing not working is the starter motor.

The headlights NOT dimming indicates the starter is not using any power.

Next check would be to see that the starter has voltage on the large cable feeding it when the key is moved to START. If it does, then check that the motor has a good ground. A test light grounded to the starter body, while moving the key to START would provide 12v to the large cable, for testing, and the bulb lighting would prove the starter is grounded. If all that happens, I'd check the starter solenoid, mounted atop the starter motor I think on models that new, to see that the small terminals are getting power when the key is in START. Don't know which small wire, but one should get power to operate the solenoid. If yours is the older design, there is no solenoid, but there is an internal switch that closes when power is applied, but you would also hear a 'clunk' as it tried to power the starter motor.
tom

 

Hi Jeff...any luck? Let us know.