VZ / LS1 Alternator Wiring Loom (Burning / Failing)

[mcsquirt]

I recently had an issue with my VZ LS1 not charging properly (the first symptom was the obvious click, click, click - flat battery).
After a jump start - checked it with a multi-meter and found the thing wasn't charging (~10V not the typical 13.8 - 14.2V).
The VZ's for some odd reason don't throw an alternator warning light if the alternator is not charging.

With 300,000 on the clock I figured it was time for a new battery & a new alternator, anyway.

On closer examination during the alternator fit up, I found that about 50mm of the wiring from the back of the alternator, close to the crimped on lug, had been fried.
In my case the connector had almost completely separated from the crimped on lug. It came apart in my hand as I tried to remove it from the stud on the alternator.
The only thing holding the cable in place was the rubber boot. This cable is a part of the main power harness wiring loom.

Picked up a second hand battery wiring loom from a wrecker and found evidence of the same problem.
The battery-alternator cable at the alternator (crimped on) end was starting to corrode & oxidise.
Checked around and found others at the wreckers where dodgy repairs had been done (soldering multiple smaller cables onto the break to fix it)

It appears that as the VZ's (LS1) age, the cables start corroding and can't handle the full current draw and the cable gets hot and corrodes some more (this cycle repeats with individual strands burning out until it fails completely).

The risk if you have a high mileage LS1 vehicle is that if the alternator cable breaks free and contacts the body you will have a dead short (un-fused) between the battery
and the body (negative), with the real possibility of a significant engine bay fire.. That cable loom is wrapped in plastic conduit and runs under the harmonic balancer in a channel that often fills up with oil & leaf litter crap.

I have since fixed the problem by cutting the old alternator cable out of the harness (Left about 200mm near the battery end - taped off that end and enclosed that in a piece of corrugated conduit.
I then replaced the old battery to alternator cable (originally rated at 140A) with a much heavier current carrying cable (went to a B & S #2- rated at around 200 Amps at 50C - I used crimped on lugs.)

If you have a VZ LS1 check your alternator / charging cable when you do your next oil change.

It may save you a lot of grief.
An engine bay fire could ruin your whole day!

Mcsquirt

[Micks]

Great advice & good find,

[R8HSVHRT]

Had the same thing happen with a VX Maloo I had auto elec said it was common on them replaced cable after alternator was changed no big deal

[ebv8]

i'm having the same issue now with my VZ, however i think its me second alternator gone and the fried cable is not the problem at this stage, i still only get a .5v drop over the cable which is within spec.
ordered a new genuine alternator this time as the china jobs just don't last
i will replace the main cable with something thicker soon though