My 03, 2.3 Ranger has been having a strange re-charge issue, here's what its doing/what I've done..

I've replaced the Battery and the Alternator (both brand new)

Whenever I drive, rev the engine the battery charge gauge shows a high charge... moves with the rev's... but this doesn't always happen... sometimes it will get stuck on a low charge.. stay there for a while then randomly jump to a high charge... while listening to the radio, you can notice the volume increase whenever the battery goes to a high charge (as well as lights exc) So its obvious this has something to do with the charging system..

I did however notice that fan clutch has gone on my truck (spins freely) could this be part of the issue?

 

Dash board Volt meter shouldn't go up and down with RPMs, that means voltage regulator inside the alternator is not working.

Purpose of the voltage regulator is to maintain a stable voltage regardless of RPM or power draw(i.e. lights, heater fan, ect...)

Now Ford did switch to a "Smart Charging" system around mid-2000's, this meant that the computer ran the voltage regulator instead of alternator.
I don't think 2003 2.3l had this but it might

On the alternator there should be 1 larger wire, Black with orange stripe, that's the B+ wire, it connects to stud/nut terminal, it is connected directly to battery positive terminal, thru a fusible link, so it should show battery voltage all the time, if you want to test it, key on or off doesn't matter.

Then on the 2.3l models there will be a two wire connector with a Yellow and a Light Green wire, these are plugged into the Voltage regulator inside the alternator

With Key off
Test battery voltage, remember that number

Unplug the 2 wire connector and test Yellow wire for voltage, should be same as battery voltage
If not then a fusible link is bad and needs to be replaced

If so test the Green wire, should be 0 volts
Turn key ON/engine off
Test green wire again, should see battery voltage
If not then fuse #11 in cab fuse box is blown(7.5amp fuse)

If voltage is low on either wire then wire is damaged somewhere, you will need to start tracing the wires back, usually near exhaust pipes is where damage can happen.



The Smart Charging systems had similar wiring and common issue they had was with these same two wires, so check that wiring harness for damage.

No, fan clutch wouldn't effect charging system
Engine temp will rise at idle then drop back down when driving if fan clutch has failed "open"
Fan is only used to cool radiator when stopped or driving slow when air flow is low, at speed air flow is OK so fan isn't needed
So symptom of failing fan clutch is rising temp gauge at idle

 

Thank you so much for your help! I'm going to troubleshoot these options and let you know tomorrow, I believe its safe to rule out that my voltage regulator is fine seeing as I just put in a brand new alternator?

Thanks again!
Alex

 

Oh, I wouldn't be so fast to assume new parts are OK

"New" used to mean "tested and works"

"New" now means "never tested by anyone, you are the first, but we will warranty the part if there is a problem found in testing it"

Back in the day when parts were expensive and labor was cheap everything got tested.
Labor is now more expensive so "quality control" was eliminated because it is simply cheaper to get free labor(the buyer) to test any parts out, and then replace them if test goes bad.

Motorcraft fuel pumps are a classic example of that, Motorcraft still tests every single fuel pump before it is shipped, so $300 for that pump
Other brands don't so you can get similar pump for $100.
But roll of the dice on the similar brand

You are the Quality Control guy on the project, lol.

 

great, who doesn't love being that guy.. especially once its back together... lol I purchased a new alternator from an aftermarket parts company (unknown) I'll run those tests tomorrow and see if its a dud o not!

 

Hey, we are our own worst enemy on that, cheap parts, cheap parts, cheap parts, that is what sells.

Why should I pay $100 for this part when I can get "the same part" for $50.
Well it is not always quite the same
Probably made to same specs and will last just as long, but..........$50 part may have 10% failure rate and $100 part 1% failure rate.
If it is easy to get to and easy to change then I would save the $50, lol, I am cheap

Alternators are easy to change, well not super hard in any case, I know the 2.3ls can be hard to get at
So why not save a few bucks

 

You said it best and two minds think alike! Lol I'm just really hoping to get this issue resolved because it has me bafflled

 

So turns out the alternator is fine, i pulled all the fuses under the hood/cab and checked/reinstalled them and now it works like brand new again! Thanks again for all your help!

 

Good work

So dirty connection on a fuse maybe?