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Yes, your GPCM and AIH were/are completely disconnected. Very strange solution to whatever the problem was. Without knowing why they did that, I don't think I would hook up either end of that wire without checking it over really well. It is possible they had the same problem as mine (burning up alts). In that case, after you check out the factory wire really well, you could just hook both ends back up AND keep the bypass wire they installed. This puts you in the same place I was at before finishing my install last week. My alternator worked great with both wires in there, because the current was able to go around the corrosion resistance inside the factory B+ wire into the bypass wire. It just isn't a proper long term solution.
Marine grade wire would be great. I didn't think to buy any. It was easier to go to the car stereo place near my work on my lunch break
Here is what I did, and it didn't take very long at all once I had all the connector ends, splices and wire. Maybe 1.5 hours total.
New 4 gauge high current wire and connector off the back of the alternator
I routed it the same way. Instead of two splices into the new cable (and much more work/parts), I just made one splice to the AIH. I then rerouted my GPCM hots to the AIH lug to pull power from there instead and save time and $.
I added an in-line fuse block. Inside are 2x150 fuses (300 amps total). After that, it goes to the lug on the starter relay.
Thanks for your help and photos. I basically did what you did, just not as well. this will get me by for now. I plan on trying to get some better crips/ connections later on. My CEL is now off for the first time since I have owned the EX!
AIH / GPCM CONNECTIONS Overview of added wires Termial block to give power to AIH/ GPCM
Good call on the terminal block. That is not a bad option at all in a pinch. A bit clunky, but it will certainly work.
The splice I used to tap off the new #4 B+ is essentially a barrel with two big set screws. It is for 0-2 gauge wire - that way I still have room to slide the #8 pigtail to the AIH into the barrel before tightening the screw down on that one end. It came with some nice heat shrink to seal the whole thing up once the screws were tightened down. Buy a little bit #8 wire (18 inches or so) in red or black (or both), some terminal lugs for #8 wire, #8 butt splice or two, and you should be set so you can eliminate that terminal block later. A heat gun and some good heat shrink are a wise investment to keep your new connections from corroding later on. I still need to heat shrink the one splice from the GPCM to the AIH lug in the photo. Either that or liquid electrical tape the splice at both ends, making sure to get the liquid tape inside the splice on both ends.
I'm having the same issue Mike the alternator that was on it when I bought it Oct 2012 was good until Aug 2015 I replaced it with one from NAPA and it lasted until June 2016 and it just went again this morning. The fusable links look good and the ground as well. I have to wonder if it's just crappy alternators. I would have hoped it would last a resonable amount of time. I may try a local rebuilder and see if I have better luck.
John... from 22 months to 10 months to 5 months... the life of each successive alternator you have installed reduced by one half from the previous alternator. Could something else be going on there?
John... from 22 months to 10 months to 5 months... the life of each successive alternator you have installed reduced by one half from the previous alternator. Could something else be going on there?
The first alternator could have been on much longer that's just when I bought it.
I've checked everything I can think of, I'm at a loss. The fuse links were 0.6 ohms and the ground was 0.4 ohms. The voltage drop across the fuse link was 0.02 volts.
I'm just using a cheap multi meter but I would say that these are reasonable numbers.
That being said the first NAPA alternator started giving me a quick flash of the battery light after about 6 months and it started coming on more and more frequently. This one just dropped to 9v and that was the end of it.
If single, then I wonder if your alternator is having to work too hard to charge failing batteries, which may be failing due to nightly parasitic drains?
If you haven't already done so, I would charge the batteries with a wall plug in charger, and then do a parasitic drain test (which will take some time, but also deplete the temporarily high surface charge simultaneously). Then, I'd load test the batteries to make sure they are really good.
You might find two simultaneous causes... like a module pulling excess power (like the radio, the GEM, a faulty door switch...) in KOEO mode, and that drain caused the batteries to exceed the number of cycles that they can be deeply discharged without damage... and your poor alternator has been trying to keep the batteries propped up.
However, if you have already done all of this, then maybe they just don't build alternators like they used to.
Well, sorry to hear you are having trouble as well. Mine has not given me trouble since I replaced the corroded B+ wire. I also replaced the whole positive harness (~$85) before figuring out it was the B+ wire providing too much resistance and making the alternator think the batteries still needed charging. This kept the alternator on all the time and burnt them up one by one.
Have you measured the voltage drop across the system with the RPMs at 2000 and everything on yet? Mine was .675 volts if I remember correctly. Now it is .1 volt, as it should be. Simple (and ideally temporary) work around is to run a second B+ wire to the starter solenoid on the fender in parallel to the stock one. Double it up on the back of the alternator and then on solenoid. This will eliminate that resistance (if you have it), and allow the alternator to cycle like it should off and on. Mine is all wired in now, and not a single symptom I had before has come back since REPLACING the B+.
All that said, they sure don't make alternators like they used to. That isn't necessarily the fault of the guys and gals building them. I was told there simply aren't any quality parts left in the supply system. All that is available are the cheap parts mass produced by the slave labor.
Corrosion is a bitch if you have it.
Last edited by Nicmike; Nov 20, 2016 at 12:41 PM.
Reason: corrected voltage drop numbers
Mike did you get rid of that extra B+ cable that you added with the inline fuse mounted on your MAP sensor bracket? Or did you leave that in place after you replaced your stock B+ charge wire?
That is the replacement for the stock wire. I cut most of the stock wire out and what remains is dead in the harness. Lots of green on it/in it. Bad news that green stuff...
I need a helicopter view of your engine bay. You've taken these gorgeously clear pics of individual details in your new power routing, but leave it to me to get lost in the trees without being able to see the forest.
In one pic, the distribution block is there, but no fuse block. In another pic, the fuse block is there but no distribution block, even though the distribution block WAS there in the previous pic... I'm getting confused... all too easy for me to do though.
... before figuring out it was the B+ wire providing too much resistance and making the alternator think the batteries still needed charging. This kept the alternator on all the time and burnt them up one by one. ....
By keeping "the alternator on all the time" I'm assuming you mean the system voltage stays up at 14.5v instead of dropping to a normal 13.5v after startup.
The stock voltmeter is difficult to see the actual voltage, but a small digital voltmeter would allow monitoring this situation.
An alternator can output over 17v which would kill a battery, but is regulated down to 13.4 - 14.8v.
That's the highest volts I've seen on ours.
The PCM is somehow involved in the regulation of the alternator.
The PCM is somehow involved in the regulation of the alternator.
Not on Mike's 2001 7.3L diesel, nor JSpence105's diesel.
I can't speak for your 2002 V10, because the engine is different, the alternator is different, and Ford did a major revamp of the electrical system in the 2002 model year. But for Mike's 2001, John's 2001, and my 2000, all pre 2002 diesels, the PCM is not involved with voltage regulation at all.
Well, sorry to hear you are having trouble as well. Mine has not given me trouble since I replaced the corroded B+ wire. I also replaced the whole positive harness (~$85) before figuring out it was the B+ wire providing too much resistance and making the alternator think the batteries still needed charging. This kept the alternator on all the time and burnt them up one by one.
Have you measured the voltage drop across the system with the RPMs at 2000 and everything on yet? Mine was .675 volts if I remember correctly. Now it is .1 volt, as it should be. Simple (and ideally temporary) work around is to run a second B+ wire to the starter solenoid on the fender in parallel to the stock one. Double it up on the back of the alternator and then on solenoid. This will eliminate that resistance (if you have it), and allow the alternator to cycle like it should off and on. Mine is all wired in now, and not a single symptom I had before has come back since REPLACING the B+.
All that said, they sure don't make alternators like they used to. That isn't necessarily the fault of the guys and gals building them. I was told there simply aren't any quality parts left in the supply system. All that is available are the cheap parts mass produced by the slave labor.
Corrosion is a bitch if you have it.
I'll measure as soon as I get a new alternator. It's starting to drive me crazy.
I need a helicopter view of your engine bay. You've taken these gorgeously clear pics of individual details in your new power routing, but leave it to me to get lost in the trees without being able to see the forest.
In one pic, the distribution block is there, but no fuse block. In another pic, the fuse block is there but no distribution block, even though the distribution block WAS there in the previous pic... I'm getting confused... all too easy for me to do though.
You are likely confusing my pics with those of the other poster who put in the distribution block to work around his problem. His GPCM and AIH were disconnected by the previous owner and bypassed.
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