So I was in my ranger sitting with the ac on and my car turned off out af nowhere. I tried to start it and nothing happen. The starter didn’t click or anything. I changed the starter, relays, ignition switch, ecu, and even got a new key bad and still nothing happens when I turn the key someone please help lol 2004 ranger

 

You can't replace ECU(engine computer) unless you have PATS(passive anti-theft system) reprogrammed, only Ford Dealer can do that for 2004-2011 Rangers
You also can't replace instrument cluster for same reason, new thing for 2004 Rangers

When you turn on the key does the "Padlock" light on the dash come on and then go OFF, or does it Flash?
If it flashes then starter will not work and engine will not run
Anti-theft is active

Bad alternator could have been original issue, you were running off battery power and when battery got too low engine stall and battery was dead so no restart

 

I changed the battery and got the old on tested still no crank no start the fuel pump won’t even prime when the key is turn to the weld on

 

I changed the battery and got the old on tested still no crank no start the fuel pump won’t even prime when the key is turn to the weld on

 

Put your old ECU back in, or have the truck towed to a Ford dealer so they can program your new ECU and new KEY to the truck.

ECU, Instrument cluster, and key need to be married to each other, only the dealer can do that.

 

Have you had luck with your issue yet? I have the exact same issue. I have power through the PCM relay to the PCM. No check engine light in ACC position at all and my scanner won't connect either.

 

No Check engine light(CEL) and no connection on OBD port means PCM is not powering up

What YEAR Ranger?

Pins 71 and 97 on the PCM should have 12volts from PCM relay with key on

Pin 55 on PCM has 12volts all the time but its just to hold memory when key is off, doesn't power the PCM

 

It's a 2006. I've been looking for that exact pin information for 3 days but I couldn't find it anywhere. Thanks very much. If I have those voltages present I'll know it's a bad PCM. If I dont I have a wire issue somewhere. Do you have a pinout diagram for the PCM connector? Thanks very much.

 

Just Google: Ford ranger PCM pin numbering

All Fords use the same 104 pin PCM, from 1995/6 and up, and main wiring pins are all the same, i.e. 12v and grounds
Most of the other pins are also the same from one model to the next.