Battery wont charge
 

2001 Ranger Edge 4.0L 5spd

Ive been going through alternators like crazy in the past year. Im on #4 now. First 2 were remanufactured autozone units then the next 1 was new from Rockauto (acdelco 95a). Currently using another ACdelco that I had tested before installing it and it passed. Thats not saying much though because one of the autozone ones would pass and once I put in the first ACdelco it solved my problems. I eliminated it being a ground, I ran a new ground to one of the mounting bolts and put it to the neg batt terminal.

Ive been using the multimeter and figured out that the light green/red wire isnt getting power when the key is turned to ON. I tested all the fuses in both boxes and theyre all ok.I just havent tested any relays. I dont have a fuse for the generator in mine. I cant figure out where the light green/red wire goes to so i can trace it and find out if its broken anywhere. My fusable links are all good as well. I really cant figure this out. Im about to just splice the green wire and put an add-a-fuse into an open switched fuse spot. Any help is appreciated. Thanks

Welcome to the forum

Yes, no 12v on green wire would be the problem

That is the instrument clusters Battery Light wire, it is the Ground for Bulb AND startup voltage for alternator.

Fuse 11 in cab fuse box sends 12v to instrument cluster and Battery Light, when key is ON.
When alternator is not spinning it is a GROUND, 0volts
So Battery Light has 12v and Ground, so it lights up.

When you start the engine, working alternator will provide 14volts, so Green wire now has 14v and FUSE also has 14v
If you hook light bulb up to 14v on both sides it goes OFF, no electricity is flowing thru it.
If alternator's voltage should drop below Battery Voltage(12v), then Battery light would start to Flicker, the lower the alternator voltage goes the brighter the Battery light would get.
Thats the point of the Battery Light or "Charge Light" on any vehicle, they all work the same.

Green wire voltage is also needed to START the alternator generating power.
Simply spinning an alternator doesn't make voltage.
You have to apply voltage to the rotor to get it to generate a magnetic field that then causes AC Voltage to be created in the Fields in the alternators case.

So no voltage on green wire with key on means no alternator generated voltage

Green wire runs to the instrument cluster

Does Battery Light work?
If it comes on then Green wire has been Ground somewhere, besides alternator
If battery light doesn't come on then check fuse 11(7.5amp) again, make sure it has voltage when key is on.

You could add KEY ON 12v to the Green wire, MUST BE key on power or battery will drain when engine is off

I checked #11 a few times and even switched it out. I probed it (#11 in the cab) with the fuse out and its working as it should. 0v with key off, batt voltage when key is on. I dont recall if my battery light is working, it may be out. I know the gauge just pegs at the bottom. I guess that means its a short somewhere thats causing this?

There is a "Bulb Test" when you turn on the key, all dash lights should come on.

Reads like you need to pull out instrument cluster and check wiring there first

Diagrams below, also included charge wiring

The Battery Light Bulb circuit also has a resistor(470 ohms) so alternator will still get the 12v on green wire if bulb is burned out

The Charging circuit in the dash is on 3rd connector C220C, pins 1 and 3
Pin 1 is 12v from Fuse 11, red wire
Pin 3 is 12v OUT to alternator, green wire


If you have a VOLT Gauge and it stays down with key on then definite problem in instrument cluster wiring

I only paid $800 for the truck so i didnt want to go through the hassle of tearing apart the dashboard. I have a race car ive been neglecting for awhile so I need to get back on that. I managed to get it fixed by putting in an add-a-fuse to the fuse box(a key on fuse) and running a line to the alternator green/red wire and it works correctly now. Thanks for your help.

Good work

Thanks for the update

Well that works - taking the cluster out isnt that hard especially the 5 speed (no fragile as eggs shift indicator cable to mess with)