I had my Octavia MK1 in for a Long Life service.

They discovered  that there had been an overheating in the fusebox that sits at the top of the battery.

The cable that comes from the alternator have been burnt at the cable lug and about 1 cm of the insulation was melted off.

See the pictures.

It has been so hot that the palstic in the box and lid have melted at the location for this cable connection.

I asked what was the cause but the man who handed over the car to me didn't know. He worked at the reception and the man who had been working with the car had gone home.

They recommended to replace the fusebox and the cable to the alternator.

So this raises some questions if someone here got the answer.

When you see the melting marks you might think it was very near to an open fire here with burning plastic..

So has this occured in just one occassion or has it been hot several times? Who knows..

And what can the cause have been?

There is a fuse (a metal fuse with part # N10424905) of 110A so if there have been a short cirquit

the fuse should have gone.

My theory is that cabel lug have come loose a little and there have been some sparking

that caused the melting.

And the shop have been thighten the nut.

Can there bee other causes?

 

Edited 5 May, 201610 yr by rail

Common issue caused by poor crimp on the Alternator cable connector.

New fuse box & cable needed.

Age old issue, also effected MK4 Golf, Audi A3 and MK1 Leon as its the same part.

Many many many many threads on this....

Well give me some links.

I have searched but couldn't find any threads.

Which search words shall I use?

 

EDIT:

I found some other threads now.

Edited 5 May, 201610 yr by rail

Search via google with briskoda in key words - site search function is a bit hit and miss at the minute due to Colin doing a lot of patching and background work in advance of "The Big Move to New Briskoda"

Edited 5 May, 201610 yr by mac11irl

Seems to be a not so unusual issue on VW group cars and others too.

Hope the new alternator wire harness I will buy is of an updated design with better connections.

I mean this is a potential cause to fire with disasterous results.

This issue must be known by VW group.

 

I have also order a new fuse/terminal box from AliExpress to a rather cheap price:

 

http://www.aliexpress.com/item/VW-Golf-4-Bora-Jetta-Beetle-Seat-Leon-Skoda-Octavia-A3-FUSE-BOX-HOLDER-FUSE-FUSES/32249984796.html

Edited 5 May, 201610 yr by rail

covered many times in the forum. I covered it in a diy guide . look in Octavia technical section [emoji106]

Sent from my iPhone using Tapatalk

advise do not just replace fuse box as mentioned generally issue is caused by resistance build up on the alternator cable and the crimps can't pass current through so get hotter and hotter . so until cable and or crimps replaced issue will still be there.

Sent from my iPhone using Tapatalk

As I understand it it's the crimp of the cabel lug  that gets old, oxidizes and then build up resistance and gets hot.

If the length of the cable is enough, if you cut it and crimp a new cable lug and then also solder it, will that prevent it from oxidize and increase the life span?

The problem must be the actual contact between the lug and the cable that gets bad of age and soldering can maybe improve the contact?

I'd just buy the proper lead or at the very least make a new one. I've seen them corrode at the alternator end too.