I have an electrical issue......

[Limited Ex]

My voltmeter is not registering much above 9-10 volts, and my battery light is on. Also noticed that the wires from the alternator to the chassis ground get really warm, and the part of the negative battery cable that runs to the same chassis ground is also warm. Not the whole cable, just the wire that shares the ground with the alternator.

Before this happened, I replaced the battery cables, and put a new alternator in. Noticed the low voltage after the new alternator went in, had it tested, and it was only putting out 11 volts. Got a replacement alternator and found it was doing the same thing. Thats when I discovered the warm wires.

First thought was to replace that wiring harness from the alternator, but I wanted some input and suggestions

Input, suggestions?

 

[seth247]

yeah sounds like coroded wiring to me.

might take an ohmmeter to that ground cable.

 

[Limited Ex]

I called Ford yesterday to see what it would cost just to replace that wiring harness. Yeah its a discontinued part So I think I will just remove it and see about making my own, or just check some junk yards and see about snagging one.

I can only hope that this is my problem.

 

[410Fortune]

build it yourself, the end that plugs into the alternator is available at your alternator rebuilder store
I have rebuilt my alternator harness a few times, because of engine/alternator changes

the factory setup was not in very good shape at all when I pulled it
crumble, stiff, full of green corrosion and undersized

the battery light usually means your alternator voltage regulator is either not hooked up to power or its not charging the battery
at idle when running you should have 14.4V at your battery + post steady
If you dont you likely need all new wiring at the battery and from the alternator to power distribution

 

[Limited Ex]

410, do the two wires that plug into the alternator itself just tie in with the ground cable? Those are the only wires that, at a glance, I am not sure where they go.

 

[BlueExpy]

Check your....

Solenoid as well, up above the battery on the passenger fenderwell. I had a similar problem, replaced the alternator, then noticed a loose nut on that solenoid.

 

[ohe_boy]

Having the same issue too! 11.7 Volts with engine running. Its intermittant though. Volt gauge will bounce around erratically. Normally its at 14.5V.

Thinking it might be a bad alternator or corroding wires.

 

[Limited Ex]

Yeah I haven't done anything about this yet. Still hoping the wires are the problem

 

[wbdonnie]

..i have a similar problem, i have been through 3 alternators, alot of the time i start the truck the battery light is on and voltage is low, but after i drive a while and get the rpms up (about 5mins) the voltage gauge goes up and i hear the alternator humm, i have a optima yellow top deep cycle battery, that i think may be something to do with it but i was also concerned about some bad wring, i guess its gonna be a headache, but i usually just trade my alternator in for a new one since i have 3yr warranty and that fixes it for a while but somethings wrong causing the alterator to fail repeatedly.

 

[ohe_boy]

Alternator change killed the battery

I swapped in a new 95 amp alternator and started it and it worked fine. Ran it for about 5 mins, did voltage check (13.8 V) and drove it to my parking space. When I tried starting it the next day. Nothing happened. No noise, lights or anything. Checked the battery and it had 1.5 V. :thumbdwn:

WTF???

 

[arco777]

Re:

Perhaps a short? That'll get wires warm in a hurry and is kinda hard on the alt.

 

[Limited Ex]

Great news! I get to keep hunting the issue!

Got in there today and took the whole harness off the vehicle and disassembled it. Discovered there is one wire that runs from the alt. to the body, with the two pigtails coming off the alt. converging into one plug that mates to the rest of the engine harness.

Replaced the wire from the body to the alt. with a bigger gauge wire, up to 4 from a 6, and found that nothing has changed

The only other thing I am considering is replacing the pigtails and wires on the other part of the alternator wiring. But I really don't see how that could possibly help.

What other components are there to the charging system that could be affected causing the battery gauge to read low voltage and the battery light to be on?

 

[seth247]

if the battery light is on it means one thing, there are two diferwnt kind of windings in an alt. The field winding creates the magnetic field, through which the generator winding turns, creating a voltage.

When you turn the car on the ignition switch sends voltage to the field winding, creating the magnetic field, when the engine starts, that signal then gets replaced by one from the alt instead of the battery, it's a self sustaining circuit, therefore the battery light goes out cause that power is now superceded by the higher voltage of the alternator.

If that light stays on when the engine is running, it means the alternator is not taking over the field. And that the alts not outing out any power.

I don't know where it's at but try and find the wire that connects the generator to the field winding, that will be the wire that takes over the field once the engine starts turning.

it may be inside the alt itself.

The fact that you've replaced the alt several times makes this seem not to be the problem. But might as well try.

 

[Limited Ex]

Haha well my problem is fixed:

Finally decided to take it to a shop where a buddy of mine works and let the people who know more than I do take a look at it. I got a phone call the next day saying they fixed the issue and my Explorer is ready to go. Come to find out it indeed was the cable coming off the alternator, but where it was bolted to the fender was the wrong location for it to be grounded. It should have been bolted onto the negative post of the solenoid it was sitting next to:biggthump And that is a condition I very possibly created myself. I just can't figure out when I would have had disconnected the wire from the solenoid, as I have had this issue for a long time now, and all the wiring work I did was performed recently.