Ford "smart charge system" alternator not charging battery

GON

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I have a 2004 Lincoln Navigator that had its engine replaced by a mechanic who knew some things but was challenged in doing things to standard. I have a few threads on BITOG about the Navigator.

After a bunch of issues, I drove the SUV from a transmission shop in Illinois to Washington state, towing a dual axle 16' enclosed trailer without issue. About three weeks ago, I decided to drive the SUV to work, about seven miles from my home. On the way to work I had a weird reaction from the gauges on the dash, just for a second. I went to work, and when it was time to go home, another wacky gauge issue, and the engine died. I was able to get the SUV running and parked the SUV at work. I have another vehicle and went home.

At home, I was unable to find my volt meter. I have about six of them, but they are boxed up. I didn't want to buy another meter. I did have my jump box handy, so I returned to the SUV and hooked up the jump box. The SUV started. As soon as I pulled the jump box the SUV died. I pulled the battery, took the battery home, and put the battery on a charger. Battery charged and passed the battery charger's test.

I put the battery in the SUV. The SUV started, while running, I pulled the ground cable off the battery, the SUV died. I still hadn't found my meter, but I assume a bad alternator. I ordered a replacement alternator from Rock Auto. Only one new Remey in stock, it was in Miami, and took nine days to arrive. No issue, I was working out of state and in no hurry for the alternator to arrive.

Yesterday was the first opportunity to replace the alternator. I only had about 90 minutes before I had other stuff to do (like cook dinner for my Wife). I did find my volt meters. I went to work, started the SUV, it showed 12.5vdc with engine running. Signs of a bad alternator (or wiring). I drove home, and just for fun I measured the volts again with the SUV running, I was now seeing 13.9vdc. Hummmm. I decided to replace the alternator. Although I have not seen many bad alternators come to back to life, I thought it would be best to replace the alternator.

First thing I noticed when I went to pull the alternator were two bolts sticking out of the top of the alternator with nothing secured by the bolts. Next thing I notices was the serpentine belt was old, the mechanic that swapped the engine was supposed to replace the serpentine belt with a new belt I provided. I replaced the alternator, and would later investigate the top two bolts. I also felt uncomfortable that only two bolts held in the alternator, both bolts on the bottom. I don't recall ever replacing an alternator with less than three mounting bolts.

I replaced the alternator, started the SUV, and only 12.5vdc. Not what I wanted to see. I did a visual inspection, nothing visually showing why the alternator was not providing voltage. What stumped me most of all was why no "battery" dummy light showing on the dash. After dinner, I looked at the parts catalog for the SUV and discovered a top mounting bracket is required for the alternator. Bracket is ford OEM 2L7Z-10153-BA. Part is discontinued. Search on Ebay, none listed for sale or completed ever. The issue is the engine in this SUV is a high demand engine, pick parts don't typically have the engine still in the vehicle, so I have some work to find this bracket.

I thought maybe the bracket helps supply a ground, and that could be the issue. I did some more research last night and discovered Ford does not let an alternator just "do its job". Ford employs a smart charge system, so the PCM tells the alternator when to release amps/ volts. So now I think I may have a bad replacement alternator, cable/ wiring issue, ground to the alternator issue, or now add a PCM problem into the mix.

This afternoon I start to do a deeper inspection. I see the two fusible links in the wiring harness from the alternator to the battery. I also see where the wiring harness connects to the battery, electric tape. I pull off the electric tape and see what I am confident is the problem. Where the alternator positive power harness connects to the battery terminal, is connected to the harness that then goes to the starter...... is connected with some sloppy solder. I take a closer look, and discover the solder is not holding the connection, and there is not a solid, or even a semisolid connection from the alternator to the battery from the positive cable harness.

I haven't decided if I will repair the harness or replace the harness with a new one. But I do know that one is at risk more and more outsourcing repairs on their vehicles. Not many Travs, Clinebargers, Wrenchturners, Timmermastechs, and the likes out there anymore.

This video from South Main Auto was very helpful in understanding the Ford "smart charge system". Especially on why there was no battery light or check engine light displaying on the dash.


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dishdude

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Pulling off the negative battery cable to test the alternator is from the Flintstone era. You do not apply this method any longer.

Yeah almost any car made in the last 40 years with a properly functioning charging system will die if you remove the negative battery terminal while running.

The "repairs" on that vehicle are sketchy at best.
 

CKN

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You have to choose mechanics wisely-and the one who installed the motor wasn't the best. The connection is at best amateurish-and if done by an "experienced mechanic" it is just sloppy.
 
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The alternator on the above picture, the head pulley is like a clutch it is suppose to spin in just one direction. If it spins backwards, it can lead to a low charging system.

In my Mom's 2006 Volvo S60, I had to replace it was making some noise and was low charging.
 
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Replace that whole mess with one of these. Under the boots are heavy screw clamps that you would attach the various red wires to.

Though I don't know what else is going on with that red wire with all the shrink and tape on it. In some vehicles it is a fusible wire, make sure it hasn't blown. There must be good continuity from the output post of the alternator to the battery + for any charging system to work.
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GON

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Replace that whole mess with one of these. Under the boots are heavy screw clamps that you would attach the various red wires to.

Though I don't know what else is going on with that red wire with all the shrink and tape on it. In some vehicles it is a fusible wire, make sure it hasn't blown. There must be good continuity from the output post of the alternator to the battery + for any charging system to work.
View attachment 119615
Thanks MK.

I was also looking at a product like this if I was unable to get the OEM cable from a pull a part:

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I would just use a high wattage soldering gun, not an underpowered soldering iron. Or a small torch and just solder it up good.

It doesn't always even get that cold here for that long and I still needed something for soldering outside in the winter.

Something like this (may or may not be the exact one):
https://www.searshometownstores.com/product/Craftsman-54046-150230W-Solder-Gun

Mine came with a case and was made in USA. Purchased sometime after 2004, possibly well after. The Harbor Freight equivalent is garbage and broke pretty quickly.

Also, those "smart" alternator charging system can be bypassed and / or reconfigured to work like a normal alternator. I would do it if I owned one.
 
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Your main connections should be mechanically connected, not soldered. You're on the right path with an OE cable or that splice connector. The minimum-minimum the previous butchers should have done was crimping a ring terminal to that loose wire and including it under one of the bolts of that aftermarket terminal connector.

Someone likely blew the fusible link... changing the alternator and letting the positive cable brush against a ground. I got a great deal on a camry that someone's non-mechanic mechanic boyfriend did this, then "the new alternator is bad too" and "if I can't fix it, sell it for scrap, nobody can."
 
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If it works like the PCM controlled alternator in the 2004 Ford Crown Vic, the alternator WILL charge even if the PCM isn't controlling it, it just defaults to some voltage like 13.2V.

To verify your repair, you may want to use a test light to check between the alternator output stud and ground. It should glow brightly even without the engine running.
 
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@GON, I’ve posted some numbers recently on the coltages in my 2018.

cold start- over 14V for a minute or less

warmed and driving around - 12.4-12.6

deceleration - over 14

headlights on, or AC on high - 13.5 steady

once a month or so, it will charge around 14 for a couple of hours of driving.
 
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If it works like the PCM controlled alternator in the 2004 Ford Crown Vic, the alternator WILL charge even if the PCM isn't controlling it, it just defaults to some voltage like 13.2V.

To verify your repair, you may want to use a test light to check between the alternator output stud and ground. It should glow brightly even without the engine running.
That must mean that a conductor from the alternator output stud runs, uninterrupted, to the battery's positive terminal (or equivalent). Is my understanding of this correct?
 

D60

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@GON I just did the CHT sensor on an '06 Expedition and had to remove the alt to do so (using the "cheater" way to sneak under the intake).

The alt bracket you reference appeared the same, so I think you could grab it off a 3V. If I'm right, your options are plentiful as 3V's are self destructing like the Terminator

I only remember because I thought the bracket was kinda unique, kinda elegant and simultaneously over-engineered ;)
 
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D60

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Here's our '08 F150 but I specifically recall the '06 Expy having the "dual horseshoe" design you spec as 2L7Z-10153-BA
 

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GM uses a similar method and actually has a current sensor on the negative cables to sense draw from the battery. I've never had an issue with it other than yes it is weird to have the car running around at 12.6 volts. However there is a method to their madness as it prevents overcharging and keeps the battery level at or around 85% I think. Every now and again it will go into what I refer to as "equalize mode in the winter" it will hit 15v for a while and then taper off to 13v.
 
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GM uses a similar method and actually has a current sensor on the negative cables to sense draw from the battery. I've never had an issue with it other than yes it is weird to have the car running around at 12.6 volts. However there is a method to their madness as it prevents overcharging and keeps the battery level at or around 85% I think. Every now and again it will go into what I refer to as "equalize mode in the winter" it will hit 15v for a while and then taper off to 13v.
There’s a shunt directly on the battery in the ford… can’t remember if it’s + or - side. my wife’s honda too, so it looks like they’ve all started going that way
 
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Smart charging systems have been around for at least 20 years. Honda used an "Electronic Load Detector" on the negative cable to sense and adjust alternator output.

My '00 WJ uses a PCM controlled alternator, but uses a battery temperature sensor to help calculate charging system output. While running, I can watch the factory volt gauge fluctuate ever so slightly, maybe a volt or two either way as the PCM adjusts for system demand.

I will say: of all the "smart" alternators out there, I've found time and again that Ford products are very particular about the quality of alternator used. Many aftermarket products just don't jive with the PCM. Until recently, I sourced my rebuilds from one of the last local vendors around, and even HIS would, on occasion, cause issues. According to him, getting a decent regulator for those units was increasingly difficult.
 

D60

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{snip}

I will say: of all the "smart" alternators out there, I've found time and again that Ford products are very particular about the quality of alternator used. Many aftermarket products just don't jive with the PCM. Until recently, I sourced my rebuilds from one of the last local vendors around, and even HIS would, on occasion, cause issues. According to him, getting a decent regulator for those units was increasingly difficult.
This x1000

There's a HUGE rash of aftermarket rebuilds triggering the BATTERY light on Fords, esp on 6.2 SuperDutys but also on earlier modulars.

They test fine at the parts store but something isn't communicating quite properly with the vehicle. Basically it's something the alternator testing systems can't detect

edit: I carry a spare alt for my '11 F350 tow pig....I ordered used OEM from a JY on ebay.
 

GON

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Earlier this morning installed a rock solid temporary fix. With engine off, 12.5VDC. With engine running, 14.5VDC.

Will be looking for the OEM positive cable assembly. Wish I was still in South Carolina, lots of pick n pulls full of 2003-2004 navigators. Only one yard in the Seattle area with a 2003-2004 Navigator. the Seattle yard is 70 miles from me, and the drive is through city interstate.

I really like these wire bridges. Quality was good, provides great confidence in the junction, and super easy to use.

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