Help! My Octavia is broken!

[Rooster]

I was driving home today in my 2003 Octavia VRs, when the ABS and Traction Control Warning Lights came on. A few seconds later the radio turned on then off a few times, then died. Next the Airbag light came on. I was only a mile from home so continued and parked up on my driveway.

I stopped the car, took the key out thenre-inserted it. Turning to the first position, the radio comes on, and the warning lights as per usual. When turning the key to the start position, all the display and dials go dead and the car won't start.

I have no idea what the fault could be, and unfortunately I left my multimeter at work today.

I hope someboday can please help me!

Thanks,

Mark.

[Raf_]

When you say it's ok till you try and start it, does the imobilizer light come on? Might also be worth checking the fuses on top of the battery as it's electrical

[mbames]

I would check the fusebox on the top of the battery (it might have melted).... or the cables from the alternator / to the starter motor.

[Rooster]

Ok, well you are definitely along the right lines - I check the fuse box on top of th ebattery and the first one on the left (from in front, facing rear) which has a think black cable coming out of it has melted and sagged. There was lots of white dust inside the cover, which has melted at the left side, and the inside is all white. Looking at the thinkness compared to the one next to it, it was probably a 110amp fuse.

I can;t see this fuse box in the manual - anyone know what that one is for (i'm guessing the starter), and what my next step should be?

Thanks.

[ExAudiSi]

Probably replace the fuse box if its melted and also the cable from the alternator to the the fuse box as that is most likely the one that is causing the problem.

[Rooster]

I'd like to understand why it has blown in such a violent way - presumable something must have caused an overload or fault that made the fusebox melt. If I replace the box and cable, is there not a danger that it will just melt again?

I was suprised at how violent it looked - I would assume a fuse is supposed to blow without melting everything around it, or is that normal??

[ExAudiSi]

I think that the cable is perhaps not quite up to the job and the ends are not crimped as well as they could be and so over time you end up with a high resistance between the cable and terminal which overheats and melts the terminal on the fusebox.

Thanks to this forum, I caught mine in time and replace the alternator cable with a new one, which appears to be heavier duty too.

I burnt my finger checking to see if the old one was getting hot

[IulianE]

I had the same problem(1st post)...the main 140A fuse(on top of the bat) was melted

[Rooster]

Thanks - that make sense. Like to understand the cause of what i'm trying to fix, to avoid it happening again.

Will call the local Skoda dealer tomorrow to see if I can get all the parts I need to fix it, otherwise it will be an expensive trailor to the garage I guess!

I do have some 4AWG cable and terminals, but no huge fuses - not really sure I want to bodge something like this though!

So just to confirm - the first cable from left (black one) is definitely the alternator?

Cheers guys.

[richm]

The failure is almost certainly due to heat generated in the (what seems very common) poor crimp on the alternator connection, effectively melts the fuse due to heat rather than overcurrent.

[mbames]

I would agree with RichM, from the comments which have been made in the past on here about people have had similar issues.

Poor crimping of the cable ends, corrosion on the contacts and in somecases people have reported that the nuts used to nip down on the fuses are loose. All of these have the potential to induce resistance, and thus generate heat..... and we all know what heat does to plastic.

However glad we have pointed you in the correct direction....

[Rooster]

well, i replaced the fuse box and offending fuse today, but could not getthe replacement cable. the dealer had trouble deciding what tgis cable went to, and at one point thought it mightbe the main loom! we settled on it probably being the alternator, and when i got home i took the battery tray and air box out.

it does go to what i think is the alternator, so at least it should be a straightforward cable swap. they didn't have one in stock, so i wirebrushed the damaged crimp and reattached. now the car will just begin to turn over, then die - like having a flat battery.

the battery is just above 12v - is it possible for the battery to have voltage but insufficient current? i will try to get the batterychecked tomorrow. i also read about the 'majic eye' indicator on the battery, which i'm pretty sure was black, indicaring discharged.

is it likely the fault has destroyed my battery?

is the cable which caused the melt likely to be damaged internally (the crimp area is still corroded) and thus causing me problems? the garage agreed that splicing some 4awg cable to replace the damaged end section may be a viable running repair until i get the replacement. any thought?

thanks again.

[Rooster]

sorry for spelling/grammer - writing on my phone.

[ExAudiSi]

The battery is probably flat from your last drive home without the alternator charging it up. Charge the battery and then have another go.

So long as the insulation on the original cable hasn't melted or cracked you should be OK until you get a new one. If in doubt see if it gets hot after a drive with some load on the electrical system.

[Rooster]

the battery was indeed flat. halford (one of the few places open on a sunday) checked it and it was beyond saving. their checker confirm it was flat, and damaged. they wanted£120fo the bosch battery which is £76at euro car parts. they wouldn't price match as ecp don't open on sundays, so i'll get one tomorrow - the alternator cable doesn't turn up until tues anyway.

if figure since i can't drive the car to the dealer, and i would be charged for them to collect the car on a trailor (plus labour for fitting) i may as well invest in a trolley jack, some axle stands and ramps, and change the cable on the drive way - don't think i can access the bolts from above.

fingers crossed all is well after new fuse box, battery and alternator cable!

is there some kind of initialisation procedure once the battery has benn off the car? after i put it back on yesterday i did leave the key in the start poition for aminute as i recall there is some maf recalibration etc. it did beep for a while, which i assume this was.

[pikpilot]

The battery is probably flat from your last drive home without the alternator charging it up. Charge the battery and then have another go.

So long as the insulation on the original cable hasn't melted or cracked you should be OK until you get a new one. If in doubt see if it gets hot after a drive with some load on the electrical system.

The problem with the original cable is that it has a high resistance in the crimp joint and so gets hot and overheats the fusebox area when the alternator is charging (around 100A). I would say you are taking a high risk of the problem reoccurring by using the old cable.

[ExAudiSi]

The problem with the original cable is that it has a high resistance in the crimp joint and so gets hot and overheats the fusebox area when the alternator is charging (around 100A). I would say you are taking a high risk of the problem reoccurring by using the old cable.

I thought that the OP said he had replaced the terminal in an earlier post, which was the only reason I thought that the car would be OK for a couple of days until the new cable turned up?

Edited 11 July, 2010 by ExAudiSi

[pikpilot]

I thought that the OP said he had replaced the terminal in an earlier post, which was the only reason I thought that the car would be OK for a couple of days until the new cable turned up?

Sorry, I missed interpreted that. As he said earlier today "the garage agreed that splicing some 4awg cable to replace the damaged end section may be a viable running repair until i get the replacement." I read that as a future event and not that it had already been done. If the crimped lug has been replaced then I agree with you.

[Rooster]

my mod would have replaced the crimp and top 8" of the damaged cable, but since i don't have a battery anyway I've decided to heed advice and wait - new cable turns up tomorrow. have been working away today, so couldn't do anything.

does anyone have experience of removing the alternator cable? with much swearing and loss of skin i was able to remove the frontmost 13mm bolt securing the cable, but it is also attached to the alternator in another place which i cannot easily reach.

what type of fastening is the second one, and is it possible to remove it in situ?

[ExAudiSi]

On the TDI, the second fastening is an 8mm nut holding a "P" cable clamp.

Don't know about the vRS, but the job wasn't too bad on my TDI 110. The worst part was getting it up to the battery box, but it's probably easier if you take the battery out. It was snowing when I changed mine which slowed me down a bit and I looked like frosty the snow man by the time I was done.

Why did I change it when it was snowing?

Well it wasn't when I started

[Rooster]

Thanks, I did play around for ages with my hands blind in the engine bay and managed to get an 8mm socket (after trying a few sizes) and bar on it at one point but wasn't sure if it was right - didn't feel like the right resistance when rotating - I thought perhaps I was still using too big a socket, or it was another plastic cap (like the front one), or a screw, or a spring washer on a post. Perhaps I was on it, and it was just already loose. I can definitely feel the P-clip, so it is probably the same - just have to spend a little more time figuring out how to access it. I have serious reservations about being able to get the new one succesfully in place and tighten up the bolts in situ, but I don;t have much choice - i'm sure it will be fine, albeit i'll loose a bit more skin!

I've already removed the air box, battery and tray, and engine covers, so fitting looks ok - just a few cable ties to cut and replace, and some plastic channels to clip it into. If I can work out how to get the

I did some searching on Briskoda on the train home, and found out how common my problem was. I did try to search originally, but think I put too many search terms in - I discovered the search works better with fewer (one) term - perhaps an issue for the moderators (?) to address (or I am inept!)

Thanks for all the help so far, ExAudiSi, and everyone else!

[ExAudiSi]

I couldn't get the nut back on the P-Clip afterwards and gave up, mainly because I couldn't feel my fingers anymore, but also because the new cable was a larger diameter than the old one, so the clip wouldn't go around it properly anyway.

[Rooster]

Picked up the cable today. Not checked the diameter against the old cable yet (just got home), but noted it had two dates on it - one in 2003, and the other feb 2010. I wonder if the first is the manufacture date (would this mean the cable may be the original (lower) spec), but would the second be some kind of shelf-life - although I can't imagine why this kind of part would have one?

Did wonder that if it was bigger that the original (as posters would suggest) that it might be too large for the clip!

I bought a long flexible shaft driver today, so hopefully will be able to get the nut back on. Away for the rest of the week but will post the results at the weekend.

Can't belive you managed it in the snow!

[ExAudiSi]

Did mine from the top, but dropped my 8mm socket into the undertray where it stayed until the weather warmed up!

[Rooster]

Had another couple of weeks away with work, and haven't had access to my laptop - appologies for not closing this off.

Parts and prices as follows:

1J0971349GN Alternator Cable 33.35 ex VAT

1J0937617D Fuse plate (fuse box) 41.35 ex VAT

N10424905 Fuse 2.26 ex VAT

Total £90.43 inc VAT

Also needed a battery

~86 +VAT from VAG

Bosch S5 battery £64.95 ex VAT from Euro Car Parts (better spec battery)

It was quite a struggle to remove the nut retaining the p-clip, but having done it I reakon it's only an hour job from start to finish.

For ease of doing the job, I would reccomend the following:

1. Disconnect the battery terminals.

2. Remove the fuse box (to be replaced), taping the cables together to hold them in order.

3. Remove the battery clamp and battery

4. Remove the battery tray

5. Remove the engine top cover and matching front trim piece

6. Unclip the two ribbed plastic hoses at the right side of the engine.

7. Remove the two bolts at front of engine holding one of the plastic tubes.

8. Bend both tubes to the left, and wedge behind bonnet prop.

9. Unclip the alternator cable from battery, taking note of cable tie / clip positions

10. using a 13mm socket, knuckle joint and extention bar, approach horizontally and unscrew the main (front) alternator cable nut

11. using 8mm socket as before, unscrew rear alternator cable nut, removing cable and p-clip.

12. Replace cable and re-assemble in reverse.

Hope this helps someone!

Rooster.

Edited 10 August, 2010 by Rooster