2003 ranger 3.0

new battery
recently replaced pcm and programmed keys after battery was hooked up wrong.

now it’s running but putting out 20v

before I replace the alternator I want to make sure it’s the issue

there are a total of 5 wires going to the alt.

3 of them go to the regulator.
- yellow (a) battery voltage present with key on or off
-white/ black (s) no voltage key on or off
-green/red wire about half a volt less then battery voltage with key on

a 4wire I believe has to do with the sensing as it’s same colour and has continuity between the wire going to the regulator. I have nothing key on/ off or running.

and the 5wire is the big one going to battery.


how do I properly test to confirm alternator is shot/ regulator is shot or something else causing it to over charge

 

Voltage regulator in the alternator is bad, period

Do NOT run the engine you WILL blow up the battery
Test volt meter on another vehicle to make sure its reading correctly, if so replace alternator/regulator

There is no "5th wire"

Just 3 and then a white jumper wire

B+ is the larger wire on stud nut terminal, out to battery

Yellow wire, feed back voltage, also out to battery

Green wire, on/off switch for alternator, has voltage only with key on

White wire is a jumper, goes from 3 wire voltage regulator plug on back of alternator to the single spade terminal next to that plug in
Picture of white/black jumper wire here: https://cimg8.ibsrv.net/gimg/www.for...bcb1cc43c7.jpg

Ignore placement and other wire colors this is JUST to show the short white jumper connections


2003 charging system below

 

Okay so how do I confirm it’s the alternator or the voltage regulator?

Voltage ge regulator is attached to the alternator so it should be replaceable I believe?

 

Yes, the voltage regulator is inside the alternator, it has the 3 wire plug
If can be replaced separately with some disassembly, but most replace the whole alternator because then you get new bearings which is another common failing on older alternators

But test your volt meter, 15-16volts DC is not uncommon on failed alternator, 18-20 is very HIGH

 

My multimeter is good.

could this have anything to do with the fusible links?

Or no? Because I have battery voltage preset going into the regulator

 

No, fusible link is just a slow blow fuse, can't increase voltage, just decrease if connections get corroded

There is nothing in the Ranger that can create voltage higher than 15volts, well the coil pack can but that 25,000+ volts, lol

Only a failing alternator can create a high than acceptable voltage