Alternator wire melting

[rkelley]

Yesterday I was driving home - when I was in my neighborhood, my radio died. After turning it on and off a few times, it came back to life. About a minute later my air bag and ABS light came on as I was coming up to a stop sign. I shut the car off and then tried to turn it back on. It turned over a few times, but wouldn't start. After trying a few times, it wouldn't turn over at all.

Jumped the car. It went about 500 feet before air bag, ABS light back on and engine died. Repeat this again. Left the car - came back about 20 minutes later, jumped it and -- hooray -- started right up and drove home.

This morning, the engine won't turn over at all.

The battery is only 6 months old. The connections are not corroded.

The alternator?? Could it just be the wire that connects from the fuse box?

[Kevin73_1]

Mine was a little different, but the same hazard lights came on. I have heard the alternator wiring harness has been a problem. Something about it being the wrong conductor and generating too much resistance and melting fusible links.

[dhc8guru]

I am not familiar with this situation on Beetles but I have seen similar situations on other cars.
With modern alternators capable of high amperage outputs, one of the flaws with them is if the connection to the battery positive side is lost, say for example you have the engine running and pull the battery + cable off the battery, the alternator is fooled into thinking it needs to charge at max output. Long explanation made short, the alternator fry's and everything its connected to along with its wiring can also fry.
My guess is the junction box is melted because the alternator was putting out its max with no place for the electricity to go or you have a bad battery connection with high resistance that created the heat.

You had a dead battery with what appears to be a functional alternator.
So there appears there is a loss off connection or a poor connection to your battery that caused the problem.
I would check the short wire going from the battery to the junction box. In your photo it visually looks OK, but pay close attention to the wire being internally corroded. I wouldn't suspect the alternator wire being bad as it appears that it had enough electricity flowing through it to build up enough heat to melt the box.

[NewBeetleMechanic]

Originally Posted by Kevin73_1

Mine was a little different, but the same hazard lights came on. I have heard the alternator wiring harness has been a problem. Something about it being the wrong conductor and generating too much resistance and melting fusible links.

Exactly what it is.


If your Beetle is doing this I recommmend you change the battery and alt. at the same time as you do the wire.

[A81Sturmer]

Could definitely be a wire. My car is a 2000, 1.8T, but those damage pics look just like my car, right now. I found that the big red wire that runs from the row of fusible links to the battery pos terminal had worn about 1/2 through from rubbing against the top of the battery. Cable with 1/2 the copper conductor worn through (frayed wires) will cause heavy current drain, resulting in this type of heat damage. Hope to buy or make a replacement wire tomorrow. The wire is about 8", right angle eyelet on one end, straight eyelet with stiff black plastic tubing forcing other end in a gradual 90 degree bend on other end. Other possibly related symtoms on my car(besides heat damage) is 30Amp AC fuse repeatedly blowing, and slow cranking. The car is running like crap too, but I blame that on other issues (fuel management/sensor/vacuum leak). But who knows, maybe the wire will fix that too! Yeah right...

[Droid]

you also need to pay close attention to where the melting occured.....im looking at that fuseblock and it appears that two of the terminals welded together....thatsa no gooda! be sure to repair if thats the case or you could haev more damage