[Heybuck]

I posted this in the LS1 section but I'm not sure if many people read it so with the moderators indulgence (I hope), I've also put it here. Thanks


So I have a 2003 Holden Caprice with the LS1 engine. I thought the alternator had died (it may well have done so), so I bought a new genuine alternator.

Pulled out the old one and was a bit shocked to find the thick cable was burnt away where it attaches to the alternator. It was hanging on literally by about 3 fine copper strands. Some super heat there or more likely high resistance?

I think the simple answer would be to run a new cable but does it run directly from the alternator to the positive pole on the battery?? Or does it transit somewhere else??

My thinking is to simply cut out the heavy cable at the battery but leave the other smaller cables alone and route the new heavy cable directly from the battery to the alternator.

My other question though is why would this happen in the first place??

Thanks, Ian

[OZZIEVILLE 67 2 door]

I think the simple answer would be to run a new cable but does it run directly from the alternator to the positive pole on the battery?? Or does it transit somewhere else??

I would think that the power is going to the fire wall then through the ignition, must be a wiring diagram on the net , or hope George will chime in
John L

[Heybuck]

Originally Posted by OZZIEVILLE 67 2 door

I think the simple answer would be to run a new cable but does it run directly from the alternator to the positive pole on the battery?? Or does it transit somewhere else??

John L

Thanks John,
That's going to be my choice. The cables are buried so very difficult to follow. It does divide so I'll make up a new lead direct alternator to battery and safely terminate to old lead and secure it it out of the way.

Ian
PS, I've asked my son in law several times if he has ever seen your car around Mt Martha. Sadly not. Maybe the new owner has moved it along??

[72projectbird]

I've always run a direct cable from the battery to the alternator on my LS stuff. Looking at my GMC, that's how the factory did it too.

Id just make a cable and run it.

[Stuart]

Was there possibly some spot where the cable was rubbing against something until there was a bare part of the copper conductor, causing a short?

[Heybuck]

Originally Posted by Stuart

Was there possibly some spot where the cable was rubbing against something until there was a bare part of the copper conductor, causing a short?

No Stuart, not at all. The cables are exceptionally well insulated and clear of any part which may rub which leaves me a couple of thoughts:

The fact that my car when I purchased it, was 15 years old and (quite alarmingly) I'm the 13th owner, who knows what might have been played with in the past. The alternator does not look very old, it was fairly clean without what I'd expect to have seen a lot of grease etc. So I'm guessing it may have been changed at some point not long before I bought the car.

When I pulled off the nut holding the cable lug to the alternator, it was tight but there were literally only about 4 strands of copper holding it to the lug.

So maybe the lug might have been poorly crimped right from the start and it slowly gave up the struggle over the years or maybe at some time before me the lug nut wasn't tightened properly. Maybe even from new?? Who would know??

Actually there is a bit more to my alternator woes. For some months now, the battery has fairly rapidly discharged if the car has sat for more than a few days. Because I only really drive it once a week or so, I got into the habit of always connecting a maintenance charger every time I put it away. The battery is only 12 months old so no issues there. But if for instance I thought I'd be using the car the next day, I didn't bother with the charger then often maybe I didn't use the car so it might have sat for a few days before I put the charger back on. In those cases, it might take 48 hours to show a full charge again. 4-5 days and it would not have enough to crank the engine.

So I had decided anyway to buy a new alternator because I suspect a bad diode might be allowing the current to flow back. The alternator I bought is a genuine GM branded unit although I note it was made by Mitsubishi but it does clearly say Made in Japan so at least I know the new one is not a cheapo Chinese knock off.

All very annoying but that's part of the price of running an older car I guess!

Ian