The Alternator Eater
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Veteran/Sheepdog
Joined: Feb 2012
Posts: 6,047
Likes: 110
From: Western AR
I really don't think you are getting bad alternator after bad alternator. There is something going on in the wiring of the truck IMO. I think you have the books. Go to Volume 1 page 414-00-25. Pinpoint Test J sounds like the one for you. Run through it. It takes 10 mins.
Start reading on page 414-00-22 under Diesel/Single generator before going to the pinpoint test.
Start reading on page 414-00-22 under Diesel/Single generator before going to the pinpoint test.
Laughing Gas
Joined: Sep 2012
Posts: 1,123
Likes: 1
From: Ontario, Canada
Hey Mike I've just redone all the tests and everything is good. I have a new alternator waiting for me not a rebuilt one so I should have an update in 30 minutes as to if it is different.
Laughing Gas
Joined: Sep 2012
Posts: 1,123
Likes: 1
From: Ontario, Canada
Update with new alternator not rebuilt.
Tests
J1 gives battery voltage
J2 gives battery voltage
J3 gives battery voltage
J4 voltage drop of 0.22V
Voltage drop to starter 0.07V
voltage drop to glow plug 0.08V
Anything else I should be checking?
Tests
J1 gives battery voltage
J2 gives battery voltage
J3 gives battery voltage
J4 voltage drop of 0.22V
Voltage drop to starter 0.07V
voltage drop to glow plug 0.08V
Anything else I should be checking?
Thread Starter
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Veteran/Sheepdog
Joined: Feb 2012
Posts: 6,047
Likes: 110
From: Western AR
.22 VDC is within the tolerances set by Ford. If you are getting the correct voltages everywhere, it should be the alternator that is causing the light to come on. Does the plug on the back of the alternator fit tight and snap in? The B+ terminal is in good shape and not burnt?
If the problem persists, next step is to make a 5 foot piece of 4 gauge wire with terminal lugs on each end and double it up on the B+ and starter solenoid like I did. That will expose whether you have an intermittent problem on your B+ wire in the harness somewhere.
If the problem persists, next step is to make a 5 foot piece of 4 gauge wire with terminal lugs on each end and double it up on the B+ and starter solenoid like I did. That will expose whether you have an intermittent problem on your B+ wire in the harness somewhere.
Laughing Gas
Joined: Sep 2012
Posts: 1,123
Likes: 1
From: Ontario, Canada
Thanks again Mike. Everything seems to be at 100% with the new alternator. Strangely enough I got $30 back when I bought a new one today and they refunded me the cost of the rebuilt one.
I don't know what the odds of getting 2 alternators that are bad out of the box are they both had the same rebuild date of 2014/07/17 maybe they had a drunk guy working that day. Thanks for all your help and hopefully this is the end of the saga for a long time.
I don't know what the odds of getting 2 alternators that are bad out of the box are they both had the same rebuild date of 2014/07/17 maybe they had a drunk guy working that day. Thanks for all your help and hopefully this is the end of the saga for a long time.
Super Moderator
Joined: Dec 2011
Posts: 13,283
Likes: 6,046
Mike... when you added your fat wire to the B+ terminal of your alternator, did the wire come with the mesh sleeve, or did you purchase the sleeving separately?
Also, you didn't just add a wire, you actually disabled your OEM wire right? Or have I again confused you with another poster?
Let's suppose for a moment that you didn't disable your OEM wire, and simply added an additional fused wire to upgrade the charging current delivery capacity of the alternator to the battery bank, without overheating the OEM wire. In that for instance, would you have attached your add on wire to the battery positive post? Or would you have still only attached your wire to the fender mounted starter relay?
Also, you didn't just add a wire, you actually disabled your OEM wire right? Or have I again confused you with another poster?
Let's suppose for a moment that you didn't disable your OEM wire, and simply added an additional fused wire to upgrade the charging current delivery capacity of the alternator to the battery bank, without overheating the OEM wire. In that for instance, would you have attached your add on wire to the battery positive post? Or would you have still only attached your wire to the fender mounted starter relay?
Thread Starter
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Veteran/Sheepdog
Joined: Feb 2012
Posts: 6,047
Likes: 110
From: Western AR
The wire came with the mesh sleeve. I added an extra wire IN ADDITION to the OEM B+, and thus had a parallel circuit for the current to run through from the alternator to the solenoid. I found that the current was running mostly through the new wire, with about 1/3 of the current running through the OEM (proof it was offering resistance to the current flow). Should have been 50/50 in a perfect circuit. I did route the new wire to the solenoid, rather than the battery positive. It was easier for me to make the connection there.
I have since cut out the corroded OEM wire and am now just running the new high current #4. I tapped off it for the glow plugs and AIH relay.
I have since cut out the corroded OEM wire and am now just running the new high current #4. I tapped off it for the glow plugs and AIH relay.
Laughing Gas
Joined: Sep 2006
Posts: 1,097
Likes: 9
From: Minnesota
All these cables you are splicing in, is it all part of the positive cable that connects the batteries and the harness's under the hood? A new positive cable is a Little over 100 bucks......
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Thread Starter
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Veteran/Sheepdog
Joined: Feb 2012
Posts: 6,047
Likes: 110
From: Western AR
A new positive battery harness was installed in my truck last year when troubleshooting this problem. It was also corroded inside...lots of green copper. It cost me about $85 from Rockauto.com. Still the same price today.
The B+ we are talking about here is part of the ENGINE HARNESS. Not the battery positive harness. It does transfer the voltage made from the alternator to the battery positive harness and the central junction box through the starter solenoid on the fender in a 00-01 truck.
The B+ we are talking about here is part of the ENGINE HARNESS. Not the battery positive harness. It does transfer the voltage made from the alternator to the battery positive harness and the central junction box through the starter solenoid on the fender in a 00-01 truck.
Fleet Mechanic
Joined: Feb 2011
Posts: 1,812
Likes: 88
From: Thousand Oaks, CA
Wow, is that an OEM Ford cable?
You can make your own with 6ft of 2AWG tinned marine cable, 2 lugs and split loom for under $40.
Even adding a 200A circuit breaker and 2 more lugs would only add $15 more.
A Ford cable is not tinned like marine cable and will more easily corrode inside.
You can make your own with 6ft of 2AWG tinned marine cable, 2 lugs and split loom for under $40.
Even adding a 200A circuit breaker and 2 more lugs would only add $15 more.
A Ford cable is not tinned like marine cable and will more easily corrode inside.
Thread Starter
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Veteran/Sheepdog
Joined: Feb 2012
Posts: 6,047
Likes: 110
From: Western AR
Thread Starter
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Veteran/Sheepdog
Joined: Feb 2012
Posts: 6,047
Likes: 110
From: Western AR
Engine harnesses, when they could be had, were between $700-1000. They can no longer be had for a Ford 7.3L unless you get one from a junkyard/salvage yard/eBay salvage. You can buy all the connector pigtails separately to fix your existing harness by splicing a new one in where needed, though.
No idea what is causing the corrosion. My truck was owned by the first (and only) owner in the North Houston area. It is possible it was submerged at some point in flood waters. It does not show on the Carfax or title if it was. My dad is an electrical engineer. He says it is possible the application of corrosion prevention measures was not done correctly at the factory when it was made (the harness). You never know if your harness was the one made on Friday right as the end of the shift came up. However, it is unlikely the battery positive and the engine harness were made at the same place and same time, so I have to suspect water submersion at some point. No other issues with the truck. No funny smells. Everything else on the truck works fine.
No idea what is causing the corrosion. My truck was owned by the first (and only) owner in the North Houston area. It is possible it was submerged at some point in flood waters. It does not show on the Carfax or title if it was. My dad is an electrical engineer. He says it is possible the application of corrosion prevention measures was not done correctly at the factory when it was made (the harness). You never know if your harness was the one made on Friday right as the end of the shift came up. However, it is unlikely the battery positive and the engine harness were made at the same place and same time, so I have to suspect water submersion at some point. No other issues with the truck. No funny smells. Everything else on the truck works fine.
Fleet Mechanic
Joined: Feb 2011
Posts: 1,812
Likes: 88
From: Thousand Oaks, CA
.. No idea what is causing the corrosion. My truck was owned by the first (and only) owner in the North Houston area. It is possible it was submerged at some point in flood waters. .... My dad is an electrical engineer. He says it is possible the application of corrosion prevention measures was not done correctly at the factory when it was made (the harness). ...
The corrosion prevention measures done by car manufacturers is mainly sealing.
I think most corrosion of electrical cables in cars is from salt.
Copper exposed to salt is why marine cables are tinned.
If you live in an area where the roads are salted, well, you know already.
If you live near the coast and get fog, there is salt in the fog.
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