95 ranger charging issues.

[mkgross419]

Hi there, 95 ranger 4.0L battery light is on and not charging. Alternator has been replaced twice(my father's truck). I'm not close to him and had limited time to look at it. I checked for battery voltage and b+ on back of alternator, it checks out. My issue is that I only have around 6 volts to the yellow wire at the alternator connector. Tried to hunt for a short in the wire but ran out of time. Wiring diagram shows that that circuit goes straight from the fuse box to the alternator, but when tracing the wire it looks like there is a connector between the 2. Im not sure what im missing but can't figure out why there is only half the battery voltage on that circuit, any help would be appreciated.

 

[Curious Hound]

I'm using a book from a 93. But it should be the same. That wire goes straight through connector #113 from engine compartment fuse block to the alternator.

Make sure the fuse is good and it's tabs are not dirty or corroded. Make sure connection at the alternator is clean and tight. Make sure your ground connections between engine block and battery negative terminal are clean and tight.

 

[mkgross419]

Sorry for the delay. I was able to get back at the truck a little bit today. I got a little more info on what happened. My father was driving the truck and all of a sudden the charging gauge dropped and the battery light came on. He had the alternator rebuilt and the light was still on. At that point he bought a new one. Still no change. He took it back and they "gave him a new one", which still didn't work. Last time I looked at it i only had 6.5 volts on the yellow circuit. Was able to get back at it today and cleaned up grounds and made sure the connector was fully seated. I now have battery voltage on the yellow circuit with the key on. The battery light is still on and it's not charging.

 

[cbxer55]

I have a 98 3.0. Battery light is either on, or blinking. I find it odd, because the volt gauge points to direct center of gauge, which is normal operating range. A volt meter to the battery tells me the brand new battery is around 14.8 volts running, and 12.6 engine off. Starts every single time, no problemo. Something must be wrong with the stupid battery light. Got it covered with a piece of black tape for now. Had the CE light covered for years the same way. Bulb finally burned out. LOL!!

CE light was on due to deleted EGR and EVAP, and cats not working any longer. Truck starts first turn of the key and runs beautifully, despite having 191,000 miles on the clock.

As to the OP's problem, I haven't a clue. If it was mine, and the truck is as old as it is, I'd junk it. Saw a R anger for sale yesterday, one of the ones with flared rear fenders. Might go and buy it just for the hell of it. Only if it's a V-6 stick. If it's a four cylinder, or automatic, I'd rather watch grass grow.

 

[RonD]

Light Green/Red wire on the 3 wire connector is the Battery Light wire, its also the ON/OFF switch for alternator

You need to have Battery Voltage at B+ and the Yellow wire, key off
In 1995 there can be a fuse for yellow wire in engine fuse box, 15amp, might be labelled GEN or ALT

With key off test light green/red wire, 0 volts
Then turn key on
Should now see battery volts, 12+volts

Battery light circuit 1995
Battery(+)----ignition switch----Fuse 15(cab)------Battery Light-----alternator

Battery light bulb gets 12v on one terminal with key on
Other terminal goes to Alternator(green/red wire)
When engine is off the alternator is in essence a "ground"
So Battery light comes on, 12v and ground at the bulb
When engine is started and alternator is "working" the green/red wire is now 12v, well 14v
And the other wire from fuse 15 is also now 14v
If a light bulb has the same voltage on both terminals then no current pass thru the bulb, so its OFF

If this green/red wire has a short to ground anywhere, the battery light can stay on even if alternator works

Ultimately you need to test battery volts with engine running
13.5v to 14.8volts is what you should see if alternator is working
If lower than 13.5v this its for sure not working

If B+ is battery volts
If yellow wire is battery volts
If green/red wire is battery volts, with Key On
Then vehicles wiring is OK, period
No 14volts with engine running means alternator is bad, period

 

[mkgross419]

I have tested battery voltage with vehicle running and it's 100% not charging. Battery is currently reading 12.1. Yellow wire is reading 11.6. Green wire is reading 11.8 with key on and 0v with key off. Green wire goes to 0v with key off. We had the "new" alternator tested and it tested bad. Replaced it with another "new" one and still having the same issue.

 

[RonD]

Yellow wire(and B+) need to read EXACTLY Battery voltage

Both are shorter wires connected directly to battery positive via fuse and fusible link(B+)

Volt meters draw close to 0 amps, so ANY voltage drop means a bad connection on the circuit somewhere
So test battery voltage first and that's EXACTLY what you should see

Key off and on will have different battery voltage, that's expected, so if you turn the key on test battery voltage again then test wires, they should be EXACTLY the same

Clean battery terminals, both
When testing voltage on alternators wires use the alternator's metal housing as the ground and then use battery Negative, if there is a difference then there is bad ground at engine/alternator


Also the white wire, the jumper on the 3 wire connector, it needs to be un-frayed, and plugged in to the single spade terminal on the back of alternator, on some you can slide it in and doesn't connect to the terminal, slides in above it or below it