Vehicle will run only on battery, its acting as if the alternator is bad but i just replaced it
will start jumped and run until battery dies
the whole dash will work then everything will go off spedometer, rpms and then my abs lights will flash then the security then it dies

 

You should always include your model of Ranger
2010 2.3l Ranger

You will need a volt meter to test the system
First, with Key on does the dash battery/charge light come on, it should, if not check fuses 9 and 10 in Cab Fuse box, one is blown, so no charging

Key OFF
On the alternator is B+ a larger RED wire
Test battery voltage first and remember it, like 12.3volts
Now test the RED B+ wire(don't need to unplug it), put black probe on alternators metal case and red probe to B+, should see exactly the same volts
If not then a Fusible link is blown, these are inside the wiring harness near the engine fuse box

If B+ has battery voltage then unplug the 2 wire connector on alternator, test the smaller RED wire, it should have Battery voltage as well, if not a different Fusible link is blown
If it has Battery volts then test the Grey wire on same connector, it should have 0 volts
Turn on the key
Retest Grey wire, it should now have 12v not exact battery volts but close, this is from battery light on dash

If all 3 wires test OK then plug back in and start engine
Test battery volts, should be over 14volts, if not the new alternator is bad, FOR SURE, not a guess, take it back

Charging system in vehicles are very simple, 3 wires, that's all there is to it
Parts stores CAN NOT test alternators, just FYI
You can


2009/2010/2011 use the same alternator wiring
2.3l doesn't have the violet wire just the red and grey on the connector

 

I found where the batter cable to alternator was seperated
connected it everythings charging and working but my radio still wont come on?
changed fuse and everything

 

Factory radio or 3rd party?

Factory will have at least 2 fuses in Cab fuse box, 6 and 24
Some also used fuse 12 as well as the above 2 fuses

 

Yea iv changed every fuse probaply even if thwy werenr blown

 

Then its a Radio problem
Pull it out and test the Fused wires first, full time 12v on 1 and key on 12v on the other

2008 diagram below, wire colors should be the same in 2010 as Ford was ending the Ranger line in 2011 so were many changes, wanted to use up current stock
Ignore fuse 22 as it is just there to MUTE audio when starting engine
Fuse 24 is full time so Clock stays current and Radio Pre-sets can be held in memory
Fuse 6 powers the radio on with key on

2004 thru 2011 Rangers use an SJB(smart junction box) as the "body computer".
Fuse box is part of the SJB, its behind passenger side kick panel

Reason I mention it is because ALL the power from the fuse box fuses come out the 4 large connectors on the SJB
The SJB connectors could get corroded, not uncommon, and of course, odd power outages
So test the wires at the radio for 12volts