HELP NEEDED TO IDENTIFY CABLE

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sussexjim
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HELP NEEDED TO IDENTIFY CABLE

Post by sussexjim »

Firstly Hello to everyone.
I have purchased a 2010 Polo 1.2 Moda for my 17 year old daughter for her 1st car but it has what im being told is called a Parasitic Battery Drain as over a week the battery will fully drain down to not even showing lights on the dash. I have fitted 2 brand new batteries & still have the problem so not the battery at fault. I got a retired mechanic friend to look at it 3 times now & he has traced the drain to the large red cable on top of the battery in the fuse board, can anyone PLEASE advise what this cable supplies as we are struggling to trace it or find a drawing or pic online.

All help very gratefully appreciated.

Many thanks

Jim
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iichel
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by iichel »

This cable supplies electricity to the main fuse box and all the interior.
So basically he traced it to everyting in your car EXCEPT the alternator (black cable), power steering (blue cable) and ABS (green/red cable).
Next step is to narrow it down any further by investigating the fuses below the dashboard and/or anything unfused.
Retali
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by Retali »

iichel wrote: Wed Apr 14, 2021 1:34 pm This cable supplies electricity to the main fuse box and all the interior.
So basically he traced it to everyting in your car EXCEPT the alternator (black cable), power steering (blue cable) and ABS (green/red cable).
Next step is to narrow it down any further by investigating the fuses below the dashboard and/or anything unfused.
Iichel , i checked my fusebox bellow with a multimeter and all the fuses's voltage dropped to zero, which means the ones fused are not the problem
How to i check the unfused ones ? I place fuses inside and check them the same way ?
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iichel
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by iichel »

what are you trying to do, retail? are you also experiencing parasitic drains?
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by CarbonChaos »

This short video may help you understand what you are dealing with and how to go about properly diagnosing the issue.

https://youtu.be/lRcj1fQcWwU
and here
https://youtu.be/APLic9F7ZsA
Retali
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by Retali »

iichel wrote: Tue Dec 06, 2022 8:52 am what are you trying to do, retail? are you also experiencing parasitic drains?
Yes, my battery is being drained. I changed yesterday the battery to a bosch S5A05 , when i park the car the voltage is 12.81 and when i take the car the other day the voltage is 12.40.
I have checked via removing the negative terminal and there is a parasitic drain of 1,35 .
Yesterday i checked with multimeter all my fuses in the fusebox and all of them are ok (their voltage is dropped to 0.00) according to humblemechanic's video.
But i saw you talking about unfused ones, so i was wondering how can i check those.

Btw i want on friday to disconnect the alternator's cable to verify if the parasitic drain comes from the alternator. But for the love of god i cant unclip the connector is too stiff and i am searching locally for
a connector remove tool.
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iichel
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by iichel »

you can just remove the black wire on the battery with a 10mm wrench. that's the positive coming from the alternator. no need to remove anything on the alternator itself.
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by Retali »

iichel wrote: Wed Dec 07, 2022 8:45 am you can just remove the black wire on the battery with a 10mm wrench. that's the positive coming from the alternator. no need to remove anything on the alternator itself.
The black wire ok. I will do this today.

From OP's photo the far left black one.
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by iichel »

Yes, that's the battery cable.

Parasitic drain testing is really easy. First you must lock the car and let it fall asleep. This takes some time.
Make sure the car thinks it's locked and closed, but it's important to have free access to fuses and relays. So close the door lock with a screw driver but keep the door open.
Do the same thing for the bonnet.

Next, position a multimeter between the negative terminal of the battery and the chassis and set to current (amps).
Make sure you'll be able to detect as low as 10 milliamps.

Next step is to remove the earth strap from the chassis, so that the only connection between the battery's negative terminal and the chassis is through the multimeter.
You'll be reading something between 0.1 and 0 amps (so 0 to 100 milliamps). If all is OK.

If not, or even if so, start pulling fuses one by one to see what it does to the current consumption.
So remove the fuse/wire to the alternator, to the ABS unit, to the cabin, etc etc. Sometimes the car wakes up and sounds the alarm/warning lights.
Then you must re-attach the earth strap to the car, unlock it, cycle ignition, lock it again and start over. Keep a close eye on the current consumption though.

I'd suggest to start at the battery and you'll probably learn that the red wire takes most current, since this is the primary feed to the cabin.
Don't forget the small blade fuses on the left of the battery.

If you narrowed down the consumption to the red wire, then the next step is to pull all fuses one by one in the cabin fuse box, below the steering wheel and keep an eye on the multimeter.

This way you can determine what fuse is responsible for the current draw(s).

Why I said unfused, sometimes people install extra equipment and do it without a fuse. Or an accessible fuse.
And some relays only take a fuse on the battery and then after the relay again. So battery --> fuse --> thick red wire --> relay --> fuse.

So you have to be systematic in this.

And take the fuse diagram from the sticky post in the 6R/6C section.
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by Retali »

iichel wrote: Wed Dec 07, 2022 10:48 am Yes, that's the battery cable.

Parasitic drain testing is really easy. First you must lock the car and let it fall asleep. This takes some time.
Make sure the car thinks it's locked and closed, but it's important to have free access to fuses and relays. So close the door lock with a screw driver but keep the door open.
Do the same thing for the bonnet.

Next, position a multimeter between the negative terminal of the battery and the chassis and set to current (amps).
Make sure you'll be able to detect as low as 10 milliamps.

Next step is to remove the earth strap from the chassis, so that the only connection between the battery's negative terminal and the chassis is through the multimeter.
You'll be reading something between 0.1 and 0 amps (so 0 to 100 milliamps). If all is OK.

If not, or even if so, start pulling fuses one by one to see what it does to the current consumption.
So remove the fuse/wire to the alternator, to the ABS unit, to the cabin, etc etc. Sometimes the car wakes up and sounds the alarm/warning lights.
Then you must re-attach the earth strap to the car, unlock it, cycle ignition, lock it again and start over. Keep a close eye on the current consumption though.

I'd suggest to start at the battery and you'll probably learn that the red wire takes most current, since this is the primary feed to the cabin.
Don't forget the small blade fuses on the left of the battery.

If you narrowed down the consumption to the red wire, then the next step is to pull all fuses one by one in the cabin fuse box, below the steering wheel and keep an eye on the multimeter.

This way you can determine what fuse is responsible for the current draw(s).

Why I said unfused, sometimes people install extra equipment and do it without a fuse. Or an accessible fuse.
And some relays only take a fuse on the battery and then after the relay again. So battery --> fuse --> thick red wire --> relay --> fuse.

So you have to be systematic in this.

And take the fuse diagram from the sticky post in the 6R/6C section.
Thanx a lot iichel for the thorough guide. This should be a sticky in my opinion.
I checked my fuses the other day by setting the multimeter at Ω and 200k and checked if the voltage of the fuses dropped. It dropped to zero . (humblemechanic's way of detecting a parasitic battery drain).

I removed the alternators cable (black) from the battery yesterday and this morning the battery's voltage has dropped from 12.86 to 12.54 , so i am guessing it is not the alternator .

Time for stupid questions : When i am locking the car, am i supposed to activate the alarm ? Do i have to have all the doors open and locked with a screwdriver or just the driver's side so i can get in and out ?
Also how do i lock the bonnet ? I am trying to lock it but it keeps opening .
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iichel
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by iichel »

just the drivers door is fine. yes turn on the alarm as well, put the car in a state that it's always in when asleep.

the bonnet, you can disconnect the connector near the lock so it thinks it's closed
Retali
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by Retali »

iichel wrote: Thu Dec 08, 2022 7:52 am just the drivers door is fine. yes turn on the alarm as well, put the car in a state that it's always in when asleep.

the bonnet, you can disconnect the connector near the lock so it thinks it's closed
Thanx man, i hope the alarm doesnt goes on while i poke with the fuses lol.
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iichel
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Re: HELP NEEDED TO IDENTIFY CABLE

Post by iichel »

if you know the right fuse, then either remove it first or don't touch it at all...
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