Mechanics

MY ALTERNATOR QUIT CHARGING AND I HAVE TRIED 4 OTHER ALTERNATORS AND NONE HAVE WORKED, ALL 4 CAME FROM JUNKYARDS.

1994 Ford Ranger • 190,000 miles

94 Ranger 4x4 4.0L My truck quit charging the battery so I assumed the alternator was bad, since then I have installed 4 other used alternators and none are charging the battery. I have checked the wiring and get 12v on the large wire from the solenoid that bolts on the back, I also show 12v on 2 of the 3 wires that plug into the alternator with key on engine off. Wiring seems to be good, battery light is on when I turn the key on and stays on when running. 12v at the back of the alt. So I assume the fusible link is good. Any ideas why I keep having problems, I doubt if all 4 alternators were bad but they could have been. Any ideas? Money is VERY tight so I don't want to spend $100 and still have the same problem.
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Bkm48198
November 5, 2011.




Here's a diagram of your charging circuit

Imma CJ Jeep kinda guy--I can maybe help you with the diagram--I know little about your rig

The Medic


Tiny
CJ MEDEVAC
Nov 5, 2011.
Here ya go.


Tiny
Fixitmr
Nov 5, 2011.
I have the 2nd diagram and have been working off of it, the battery light comes on so I have 12v thru that wire (LG/R), I also have 12v at the (Y/W) wire and 0v on the (W/BK) with key on engine off.I have only seen 1 fusible link by the solenoid and it checks out good with 12v at the back of the alternator. Fuses all check out good but no charge when running.


Tiny
Bkm48198
Nov 5, 2011.
I always take the alternator to the auto store for testing when I get them from bone yard. That way I know any problems originate with vehicle.


Tiny
Fixitmr
Nov 5, 2011.
I made the alternator work by running 12v to the G/R & Y/W wires so I know the alternator is good, took the 12v off the Y/W wire and get no charge so I ran 12v from battery to Y/W wire only (OE wiring on G/R) and get charge but the battery light stays on in the truck, getting about 14.6v to the battery now. Battery charger is on now charging it because it was down under 12v. Thru the OE wiring when running I had 1.9v on Y/W wire and 6v on G/R wire, tried different fuses in power box under hood( 40a & 15A) with no changes. Something is still wrong but at least I know the alternator is good.


Tiny
Bkm48198
Nov 5, 2011.
CHECK YOUR FUSES!---YOUR OWNERS MANUAL MAY SHOW YOU LOCATIONS THAT YOU KNEW NOTHING ABOUT!

REMOVE AND REPLACE "SUSPECT" FUSES SEVERAL TIMES--THIS MAY SCRAPE OFF CORROSION AND GIVE THEM BETTER CONTACT!

Are the wires to your solenoid hooked up correctly?

Try the stuff below (actions),

IN MOST CASES THIS IS THE PROBLEM!

PEOPLE GET LAZY!----THEY DO NOT ACTUALLY DO THIS STUFF

IT BITES 'EM IN THE BUTT. THEY COULDA BEEN RIDING LONG AGO!

TAKE STUFF LOOSECLEAN"SCOOCH" THE CONNECTORS AROUND----TIGHTEN THE NUTS OR BOLTS WELL! DO NOT JUST PASS OFF ANY BIG CABLE CONNECTION AS, "IT LOOKS GOOD".

DIELECTRIC GREASE IS YOUR FRIEND, APPLY TO CONNECTIONS--FUSES--RELAYS ETC.

KEEP US POSTED

THE MEDIC
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Tiny
CJ MEDEVAC
Nov 5, 2011.
Fuses are all good, tried other fuses from my wife's car. Solenoid wires have not been touched in years, everything else works properly other than the charge circuit, I will try unhooking the solenoid and cleaning the terminal to see if that makes any difference but it shouldn't, the Y/W wire comes from the power box under the hood not straight from the solenoid. The things that I wonder about is if there is another fusible link somewhere that I have not found, and why does the voltage on the Y/W wire drop from 12v down to about 1.9v after starting the motor? I have a Chilton manual and have the wiring diagram for a 94 ranger and it shows the Y/W wire being straight thru from the 15a fuse to the alternator. I went and bought wire and connectors today so I can replace the wire tomorrow and see if that makes any difference.


Tiny
Bkm48198
Nov 5, 2011.
OK THE PIC I POSTED EARLIER WAS NOT THE ONE I MEANT TO

I WENT BACK INTO MITCHEL I, THIS IS THE ONE I MEANT TO POST

I REALLY HOPE WHEN YOU CLEAN THE SOLENOID CONNECTIONS, ALL WILL BE GOOD. ANY OTHER CONNECTIONS THAT ARE THERE (SNAP TOGETHER SMALLER WIRES, IN THE SYSTEM) MIGHT PULL THEM APART A FEW TIMES, DO THE DIELECTRIC GREASE THING TO THEM ALSO.

HERE'S THE RIGHT PIC

KEEP US POSTED

THE MEDIC


Tiny
CJ MEDEVAC
Nov 6, 2011.
Yah, that 1 only shows 1 fuselink. Which is what he has.


Tiny
Fixitmr
Nov 6, 2011.
HOW ARE YOU DETERMINING YOUR VOLTAGE

GAUGE IN TRUCK---OR A PORTABLE VOLTMETER?

JUST FOR MAKING SURE YOU DO NOT KNOW ANOTHER FELLER WITH A POST HERE, THE TRUCK MUST BE RUNNING IN ORDER TO CHARGE THE BATTERY!

IF YOU HAD ONE OF THESE, YOU'D BE RIDIN' RIGHT NOW. LOL!

THE MEDIC


Tiny
CJ MEDEVAC
Nov 6, 2011.

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