2003 Ranger Alternator Mystery
 

Hi Guys,
my first question on this forum. I am about to go crazy here :)
It's been a week that i am trying to fix my 2003 Ranger.
It has 4.0 sohc engine.

a week ago , I started my ranger and battery charge light came on.
The weird thing was that it was comming on with different intensity as if the wire was lose.

Well, i tought it's time to check battery and alternator.
Took it to the local parts store and battery checked-out fine.
They could not test my alternator since they did not have an adapter for ford.
So i took it to another store and this time they did not have ford alternator electrical connector. Five stores later i finally gave up and order another used alt from e-bay.
Alt came in and i installed it and same thing happened.
Charging lite is on and it does not charge the battery. I have avbout 12.20 volts on the battery when checked with volt metar.

Did lot's of troubleshooting with help from another site and could not fix it.
So i said, maybe i got non-functional used alt. Let's get the new alt. After buying new and installing it I got the same issue.
So this is where I am right now:

black/orange (b+) terminal is producing same voltage as on the positive battery terminal.
the voltage depends of charged state of my battery. When it's fully charged it reads 12.65 v. When i let the track idle for 5-10 minutes drops below 12.


I disconnected black/orange (b+) wire
and connected volt meter directly to the alt output.
While idling it produces, about 15-20 volts

If i increase RPM`s it gives me up to 45 volts.
When i connect black/orange wire back it gives me same
output that I have on the battery (12 volts)

yellow/white wire gives me about 2 volts less the the battery so about 10 Volts while truck is running.
When it`s not running it gives me same reading as on B+ Terminal (12 volts)

Black/white and another white (s terminal) wires are connected and it does not appear that any fusable links are bad.
I have checked all fuses and they all look good.

I am at this point willing to take any ideas to try to resolve this issue?

Cheers
Alex

Clean the negative (ground) connections from the battery to the frame and body and engine.

Hi,
Wow, I just cleaned small wire connector going from negative battery terminal to the frame and now started partially charging.
The red light goes on and off and i could see lights getting bright and then dim again so i will continue and clean other connections to the frame and engine.
Would you know where main frame connection is located?

Thank you very much. I am almost there :)
Alex