i replaced the alternator and its still not charging

[it-broke-again]

I have a 2002 ford ranger 4.0l 4x4 auto trans and it ran great until the other day when the battery light came on and later it would not start. I tested it with a voltage meter after I jump started it with my car and the voltage was bouncing between 11v and 15.8v. so I figured the voltage regulator in the alternator had went bad and bought another alternator to replace it only to find out that now its not charging at all. I took the replacement back and swapped it as if defective and still got the same results. I have a full 12 v running to the alternator post at all times, the yellow/white wire running to the regulator has a full 12v at all times, the white/black wire I tested for resistance between the connections and got none but the light green/red wire is only getting like 1.4v is this normal? and if so can someone please tell me what I'm missing here. I'm at a loss and don't want to have to dump a whole bunch of money into a shop because its not the best looking truck to say the least

 

[Raser13]

If it's like older fords the light or gauge was integral to the charging system. If your bulb blew or the gauge went your alt would stop charging. One of the dumbest things I've ever seen. So if your gauge cluster light blew after it came on that may be it. If not idk.

 

[it-broke-again]

I'll have to check the bulb the batt light stopped workng after the old alternator died

Sent from my XT1028 using Tapatalk

 

[RonD]

I'll have to check the bulb the batt light stopped workng after the old alternator died

Sent from my XT1028 using Tapatalk

It will be the fuse, not the bulb, look at your other thread about this.

The circuit has a resistor inline so if bulb does burn out alternator will still work.

 

[it-broke-again]

Well my fuse tests and looks good in the fuse box and if it is a fuseable link in the wire where can I find it or would it just be easier to restring a new wire

Sent from my XT1028 using Tapatalk

 

[it-broke-again]

Is it also possible that the resistor has failed causing there to be no connection if the bulb burnt

Sent from my XT1028 using Tapatalk

 

[RonD]

Is it also possible that the resistor has failed causing there to be no connection if the bulb burnt

Sent from my XT1028 using Tapatalk

That would be a long shot, not impossible, just not likely.

read here, your other post: http://www.therangerstation.com/forums/showthread.php?t=166634

test wires as stated

And check the in cab fuse panel for #11 7.5amp, thats the battery light fuse on a 2002, I checked

Fuses are test with an OHM meter, not an eyeball, women are tested with an eyeball, there are other differences as well....fuses and women that is

 

[it-broke-again]

I have tested the fuse with a ohm meter three times now and it is good but no light comes on fit the battery light, I have no charge from alternator, and still low voltage at the green/red wire

Sent from my XT1028 using Tapatalk

 

[RonD]

I have tested the fuse with a ohm meter three times now and it is good but no light comes on fit the battery light, I have no charge from alternator, and still low voltage at the green/red wire

Sent from my XT1028 using Tapatalk

May be thats the wrong fuse, with fuse out, key on, is the low voltage on the green wire gone?
It should be if thats the right fuse.
It will be a 7.5amp fuse

Alternator is OFF if there is not 12volts on the green wire
An alternator will run down the battery if left ON, so it needs to have an ON/OFF switch, thats the green wire

The Battery light is used because if alternator is ON but not spinning(generating voltage) then it is a Ground, with 12volts from the fuse and a Ground at the alternator the Battery Light Bulb is ON.
When alternator spins, engine running, the green wire now has voltage from the alternator, same voltage as at the fuse, so with no Ground the Battery Light goes off.
If alternator quits generating power, broken, then green wire is now a Ground again so Battery Light comes ON

 

[Willcastle]

The alternator will not work properly with the batt. Light not operational

 

[it-broke-again]

Idk for sure I'll have to check tomorrow after work but I'm pretty sure it's the right fuse from the wiring diagram in looking at

Sent from my XT1028 using Tapatalk

 

[it-broke-again]

Is there a way to bypass the battery gauge and properly give the alternator 12v to the green wire. Also I checked the bulb in the cluster and it seems to be OK and the gauge still reads battery voltage so I don't believe the gauge is bad

Sent from my XT1028 using Tapatalk

 

[RonD]

Voltage gauge isn't part of the circuit, in your year

You can temporarily hook the green wire to any Key on 12volt source.

Looks like Fuse #41(20amp) in engine fuse box only has power when key is on, check that.

If so then cut the green wire, and run a jumper wire to fuse #41.
That should get charging working again.

 

[it-broke-again]

I'll try this after work and come back with my results

Sent from my XT1028 using Tapatalk

 

[it-broke-again]

And just out of curiosity what is run off of fuse 41

Sent from my XT1028 using Tapatalk