Battery drainage even after new alternator

[sscaifeuk]

Can anyone advise on my 55 plate 1.9td automatic please.
Just before xmas I went away, half way into my hour and a half journey I suddenly had the ABS light then the air-bag light come on. I needed fuel, so stopped at the services, filled up, then the car wouldn't start again, as if it had a flat battery. Someone gave the car a jump start and it started, so I continued my journey, minus the radio etc cause I thought perhaps I was having battery trouble. I arrived at my destination on the Thursday. Checked the car Friday and it started, didn't bother Saturday, but come Sunday when we were ready to come home, it needed a jump start again. Drove all the way home minus any extra electricals again. It started the following morning, so I took my husband to his hospital app on the Monday and on the way the ABS light came on when I touched the brakes, then the wipers stopped. I sat in the carpark with the car running and watched as everything gradually died, from the ABS light showing, then the air-bag followed by the brake system light flashing and beeping and finally as the dash lights disappeared, the battery/charging circuit light came on . I have had no engine management light come on. Have done a diagnostic check anyway and nothing came up, so guessed it was an alternator problem.
I Changed the alternator at the weekend, cause I need the car going and tonight it died again. My dad has given me a battery off one of his vehicles for me to swap with mine in the morning to see if its the battery as well. All signs at the beginning was battery, the finale was alternator, am I missing something??  When ever I have had battery or alternator problems in the past, the battery light has come on first or could there be an electrical fault somewhere draining the battery being it was the ABS light that came on first. Has anyone else had this problem or something similar??? I don't have money to waste at the moment and go into hospital for a big op next wk and wont be able to walk far afterwards, so my car is going to be my life line for about 6wks (expected recovery period). Any help or advise would be gratefully received. Sonia

[Chrispb]

Hello and 
First of all check out your battery fuse box see if you have any overheating/melting see link below.

https://www.fordmpv.com/smf2/ford-galaxy-reference-library/battery-junction-boxauxiliary-fuse-box-repair/

[Mirez]

Hi Sonia and welcome!

The lack of alternator/charge light would make me think its a battery fault for sure, how old is the battery? A common misconception is that the light will come on when the battery voltage is low but in reality the charge light will only illuminate when the alternator isnt putting out a suitable charge voltage, typically on these its about 13.2V and below. I know you have already changed the alternator but I susoect your problem is much more likely to be a cell dying within the battery.

[Caitlin]

I dont understand that? if the alternator is putting out 13 volts how is that not what the battery has???

[Chrispb]

I dont understand that? if the alternator is putting out 13 volts how is that not what the battery has???

The battery fuse box is the link between the battery and alternator, if there is a high resistance between the alternator and battery the battery won't receive the full charging current.

The crimped terminals in the fuse box were never soldered when new, over a period of time oxidation takes place causing a high resistance and overheating/meltdown results

[Mirez]

Let me clarify, when the engine is running the alternator is looking after the electrical systems providing power for them and charging the battery. When the engines off the system is powered by the battery only. The light will come on only when the alternators output is sub 13ishV but yes the battery will get the same voltage as the alternators putting out BUT once the alternators off it will drop back to its own voltage.

Batteries fail in many ways, one of which is when a cell dies. The battery may still show as having a good 12.something voltage but as soon as a load is applied it dies. When they fail in this way they often draw a large charge current when he alternator is runing which causes the symptoms Sonia has.

[sscaifeuk]

Thanks for the replies, i'll swap my dads battery for mine tomorrow and give it a good drive around, Fingers crossed it solves the problem and ill just have to replace the battery. I'll have a look at the electrical terminals too just to double check there is nothing going on there anyway. Thanks again folks. Must say this site is brilliant, wish I had found it a while ago.

[sscaifeuk]

Thanks to you lovely people. Look what I found. Now to source the replacement.

[Chrispb]

I got one from Here a few weeks ago.

I still stripped the new one down and soldered both ends of the red lead attached to the new box, you will need a new crimp terninal to repair the large black wire or you could replace the lead which goes down to the alternator but whatever option you decide please solder the crimps as shown in the first link.
The other large black lead on the next fuse should also be soldered aswell, this is the power supply to the internal central fuse box.

Good chance your original battery will be OK after 36hrs on charge, shame you hadn't looked before on here before changing alternator.

[sscaifeuk]

Thanks for that,  I didn't actually find this forum till after I had bought the replacement alternator unfortunately for me  but  without it I dont think I would of found tge fault myself.

[sscaifeuk]

Found the part in my local scrap yard this morning and have replaced it and so far car is running fine. Thanks again to people in this forum for your help, just wish I had you before I wasted money on a new alternator.

[Chrispb]

Did you replace the whole cable or just the crimp terminal? if you only replaced the box without repair/replacing/soldering then the replacement box will be short lived as you will have a repeat situation!

[sscaifeuk]

For now its just the replacement box and a clean up of the terminal as I dont have access to a soldering iron at home. I go into hospital Tuesday for a big op, so will sort the main of the soldering afterwards. Hopefully i'll find a friend who can do it or I will have to purchase something myself.

[Chrispb]

OK I hope all goes  well for you, unfortunately we're quite a distance apart for me to help, would take about half an hour to an hour to fix.
Someone else nearer may offer to help, a blow lamp is the ideal tool to use as it heats very quickly.
At least you know where the problem is but can't stress enough that you need to do this asap to avoid further damage to fuse box and alternator.

[sscaifeuk]

Having thought we had solved the problem, by replacing the battery fusebox, the car is still draining the battery. The alternator wire, once the initial rubber casing that had melted was removed from the wire, was not damaged, so we temporarily taped the wire after a clean up and re-used the same wire until I could get it soldered, should I of replaced that too? At the moment I can only use the car while the weather is dry and on short journeys in daylight, as soon as I turn on wipers, lights, heater, etc the battery drains, am I missing something? This is so stressing me as I have just come out of hospital, can't walk far and hubby is supposed to be using the car to transport me about places as its my/our only vehicle. My dad has just bought an amp meter thing to check the voltage giving out but has not been round yet cause of work. Hoping he can find something if you are all out of ideas. what I dont get is why its the ABS light and the airbag light that comes on first, when the battery is dying. Should I be looking at a fault with the wires to here???

[Chrispb]

I'm sorry your having a stressing time, but be assured were  also having a stressing time when people don't follow the advice freely given.
The fault you have with your car is not unique the fault with your car is the crimp terminal on the alternator cable, the melting fuse box is the result not the cause, the cause is the resistance between the copper cable and the crimp terminal not the terminal and the fuse box.

When you said you had only replaced the box and not repaired the terminal I told you it would be short lived and would happen again.

You cannot possibly expect the alternator to charge the battery properly with the wire in this state!!!

[mickyfin]

I have had exactly the same problem,  I got the air-bag light coming on and then the ABS light a flat battery and then it would not start.
The error codes being low voltage on both ABS and the Air-bag system (garage read them for me). The Fuse box had burned and the cable was in a bad state.
My initial fix was to cut back the cable and fit a new ring connector (soldered and crimped). I cleaned the connections and put it back together and the car worked great. I ordered a replacement fuse box as the melted bit no longer closed and sealed.
I did not fit it initially as my fix seemed OK.
This seem to last about a month now I have got the same problem again in that the car lacks power and I am getting the low voltage error (Air-bag and then ABS) not all the time but it is seeming to become more frequent, the connectors are all fine no sign of burning and I have tested them under load and they get slightly warm (I switched every electrical device on in the car I could). But the battery was still getting charged or it seem to be 13.9v with everything on.
My battery without the engine on is 12.5v with the engine ticking over 14.5v so it does seem like the battery is charging.
Just in case now I have replaced the fuse box completely and still have the problem.
I have purchased a new battery (decided as it was 4.5 years old) but not put that on yet, I am thinking about replacing the cable fully from the alternator to the fuse box but not sure where I can purchase one long enough. Plus I not sure how difficult this will be, would I be able to cut the end of the existing cable, pull it through the armour and then replace it with a new one. (I know I would have to crimp and solder a new connector on the new cable but happy doing that)

I have not managed to recreate the fault in my drive way only when the car is driving along, the car also past it MOT while it has had this issue. I can though tell a difference in power in the car and when going down a a hill and the car is coasting it seems I notice it more.

When the Air-bag light comes on the car stutters loses power then picks up again and light goes out. 
Chrispb you seem to have experience with this issue so do you have any other suggestions? i.e. could it be the smart charging system or alternator and is there an easy way to diagnose.

     

[Chrispb]

Low battery voltage can play havoc with the modern systems, the fact that your wiring/terminals are getting warm in the fuse box means you still have a problem with high resistance.

With your multitester probe the battery and keeping the - lead on the battery now probe the short red lead that links the battery to the battery fuse box then the two black leads, any resistance here will give varying readings.

If the alternator lead is badly oxidised then replacement will be necessary don't forget to solder the crimps on any new lead to prevent further problems and don't overlook the other large lead next to the alternator lead in the battery fuse box as this one supplies the central fuse box inside the car.

Also don't rely on the alternator charging a flat battery sufficiently you need to put it on charge for a minimum of 24hrs ideally 36hrs

[mickyfin]

Problem not solved by new battery, went for a drive and got the Air Bag light on and a loss of power, it flashes for a few seconds during which the cars power seem to go (Almost like stalling)

I have a new cable on order to replace the cable between the alternator and fuse box so will see if this helps.
I am slowly coming to the conclusion it is the alternator or the Smart charge system and may just need to take it to the ford garage to fix.

Do you think an electrical short somewhere could cause this? i.e. electric window

I have thought about a test while driving but it means running a cable from the battery in to the cabin and just monitoring the voltage on the battery with my multimeter, while driving along (well my son doing it for me)

Thinking about this I  might be able to do it just connecting to the 12v aux port in the back as it really is the car voltage I need to monitor, what I think I am looking for is a big drop in voltage.

Have previous people solved the problem ?   

Any advice received with thanks!

[Chrispb]

Get the battery box sorted asap, when you get your new cable it's advisible to solder that and the short link cable on the new fuse box.
What I would also advise is you get yourself a VCDS lite cable like this one Link
As you also seem to have limp mode problems aswell, you can then scan your various modules for fault codes which can help with diagnosis.

[GAZMC1973]

Hi anyone know the part no,s for the alternator cable and box pls found box on ebay but not cable and as i have no driveable car ATM don't want to get off eBay and wait as need car for work oh and if anyone knows partno. for injector wiring loom too that would be great 

[Chrispb]

Hi Gary 

Battery fuse box 7M3937548A (VW number)

Alternator lead. VW Numbers.
Pre May 2001 . 7M3971349BA
post May 2001. 7M3971349CA

Injector wiring loom is 038971600 (VW number)

[GAZMC1973]

Thank you very much that's a great help are ford parts numbers the same? although prob go to vw just in case they not got in stock might have to ring ford.

[insanitybeard]

The alternator- battery fusebox lead finis (Ford part number) is 1495874 (bloody expensive for what it is though- at least if you buy it from Ford), this is at least applicable to my 130ps TDI on a '54 plate, but worth confirming that this is applicable to your vehicle, not sure about the battery fusebox part no. Ford's part numbers are different to VW's but in the case of these parts the items should be exactly the same.

[Chrispb]

Hi Gary
These sort of parts are usually quite a bit cheaper at VW, if you go to or ring VW don't tell them the reg no just tell them it's for a Sharan with your year and engine code 115=AUY.
You can then ring Ford and compare prices.

[GAZMC1973]

Hi quick update battery box and lead no more expensive at ford and they have instock which vw dont (vw guy on phone said no one asks for them yeah right mate ) however struggling to get a injector wiring loom vw said they can get one in a few days price Ã,£63 vw ford Ã,£135

[Chrispb]

Injector looms are on ebay for Ã,£60 ish as are new and old the battery fuse boxes, didn't see any leads though.