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Discussion Starter · #1 ·
So I was driving to a job and on the way up the battery light start flickering, so I took it to the mechanic and he said it was the alternator. This was ****ty because the wilson alternator was just out of warranty, so I had him put in a new one (not remanufactured). Here I am one month later the battery light comes on again, I am no longer working in that town so I take it another mechanic, he replaces one of the wires leads to the alternator calls it fixed. Next day battery light comes on for 10 minutes straight but the battery gauge on the dash is in normal range. So I drive it back to the shop so he can put a voltmeter on it, except right before the shop the light turns off. He puts the voltmeter on it and it reads normal. I have been driving a few days still no light. I checked the fuses, and the entire electrical system was checked out when the alternator was replaced. The new alternator is under warranty still but I am not certain it is the culprit. Does anybody have any ideas?
 

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Multimeter time!! This is what I'd do, and have done before.

Start taking volt measurements. With the system off, measure the battery post to post, connector to connector. Should be just about no difference. If you have two batteries, do this one at a time.

Next, hook to a + Battery post and move to various grounds, not necessarily grounding points, and look for differences. Now, make sure to measure before and after the alternator.

Differences mean volts are being lost for bad grounds.

Now turn the vehicle on and take a voltage reading from the + alternator to the alternator frame, and various ground points, some thing: looking for differences. I don't know the 96 7.3, so I don't knwo the alternator config nor how many batteries it has.

Trace the big battery wires as far as you can looking for cracks in the shielding, frays, mouse nests, etc.

That's the easy part. Now clean the battery terminals. Remove the grounds and clean the grounds. This includes removing the alternator and cleaning where it attaches and the alternator itself. It also includes tracing that big black wire down to the frame and cleaning that. I use a wire brush, but if it's shiny when it's done it's good.

I had something similar happen to me in my car. I replaced the alternator, but when I was replacing the alternator, I saw a bubble in the red insulation. Turned out someone had replaced a section of the battery to Alternator cable and did so with something four gauges thinner, which get to hot. Perhaps that could have turned to a fire if it was not caught. I think two different sized wires is a fusible link and could be an acceptable practice in the right place. When I found the bad wire, I had a shop replace the alternator three years prior and I think they cut the cable and installed a new section for some reason with wire gauge 4 AWG too small, which caused the flashing reading for me.

Others with problems like this have found their thick positive or negative cables frayed inside the insulation in a hard to see area, like needing to move the radiator to see it. This is very hard to find because frayed wires will not show up in an ohm check, a volt check of the battery with the system off, or a volt check at idle, because there just is not enough amps to go through the wire.

I'm not saying get yourself battery cable and to start crimping and soldering lugs unless you see something in the wiring that justifies it.
 

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I am NOT saying this is it, but the only time I have ever had my battery light come on (2003 7.3 Excursion) is when I had a bad glow plug pack.
It sucked the battery to ZERO in about one hour WHILE DRIVING.
unplugged the harness and recharged it, and all was good.
Just something else to check. If you are still in warm weather, you can just leave it unplugged.

Sent from my E6810 using Tapatalk
 

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Discussion Starter · #5 ·
I am NOT saying this is it, but the only time I have ever had my battery light come on (2003 7.3 Excursion) is when I had a bad glow plug pack.
It sucked the battery to ZERO in about one hour WHILE DRIVING.
unplugged the harness and recharged it, and all was good.
Just something else to check. If you are still in warm weather, you can just leave it unplugged.

Sent from my E6810 using Tapatalk
Yeah its not currently dying on me, its more when I get called to a job I need to drive 1000km plus so I am worried it will die enroute. I did have the glow bulbs test last year and they were good. I am just worried its going to get worse when I need it for work. Thanks for the help
 
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