It seems that my truck's internal computer isn't telling the alternator (new) to charge the battery (also new). I'm aty wits end trying to remedy this.

Any of you pros have any suggestions?

 

2003 Ranger
2.3l. 3.0l, 4.0l engine???

I doubt its the smart charging system

When you turn the Key On does the Battery Light come on and stay on(engine off)
If not then fuse 11 in the cab fuse box is blown/bad, replace it, 7.5amp
This is the ON/OFF switch for alternator

New alternators often don't work, just FYI, some people have to get 2 to 4 replacements to get a good one

So lets test some wires at the alternator to see if the Rangers side is OK
This is for V6 Rangers, 3.0l/4.0l engines

Test battery volts, 12.3v to 12.9v is expected, remember that number
KEY OFF
Put Volt Meter's Black probe on the Alternators metal case, thats the GROUND for all tests

Put Red probe on B+, thats the larger terminal with the stud/nut, should see Battery Voltage, what you remembered, exactly
If not then a Fusible link has Blown in the harness near the engine fuse box

Unplug the 3 wire connector on alternator, the voltage regulator wires
Test Yellow wire, should see Battery Volts exactly
If not a different Fusible Link is blown

Test Green wire, should be 0 volts
Turn Key ON
Retest green wire, should now see Battery Volts, but this one can be a little less now
If not then Fuse 11 is blown

If all 3 wires tested as OK, then Ranger wire is PERFECT, 100%, no doubts at all

Plug 3 wire connector back in
Start engine

Test battery volts, should be 13.5 to 14.9volts, if so alternator is working
If not alternator is bad, this is not a guess

And just FYI, there is no parts store on the planet that can test an alternator, well to be fair I only know about the US and Canada parts stores, and they can NOT test an alternator
And Starter motors either, always bugged me when they started trying to test these two things
YOU can test them, ON THE VEHICLE

 

I'll do all of this. Btw it's a 2003 Ford ranger edge 4x2 5-speed 3.0l v6