inertmitant battery light fault!!!

Hi folks, I have a 1996 300tdi ES and the other day the battery light flickered while i was driving, this followed with a loss of power then it cut out. I found the live to the battery had come loose, so sorted that out and started her up, she fired up with no problems. So i thought the problem was sorted, next day the same thing happened again, loss of power and cut out, this time i had no battery warning light, but she still fired straight up.
So i have done alsorts of tests witha multi meter, the alternater is working as it should, the battery is good but i did find some bad wiring that i have sorted out or removed as it wasnt needed.
I replaced the battery light feed plug to the alternator as it was in poor condition, put in the key and turned to 1, battery light came on and went off when started, so i tought job done, so i left it for a while then came to start it again, no battery light again!!!! any ideas would be a great help.
Its a new disco and ive had it for about 4 weeks and had no problems at all before.

If the battery light does not come on, remove the wire from the D+ at the alternator and ground it. If the light still does not come on, the fault is the power to the bulb, the bulb or the wiring. If the bulb does light when you do the test, suspect the alternator on the blink.

Datatek said:

If the battery light does not come on, remove the wire from the D+ at the alternator and ground it. If the light still does not come on, the fault is the power to the bulb, the bulb or the wiring. If the bulb does light when you do the test, suspect the alternator on the blink.

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Top man, thanks. I will give that a go tomorrow and post how ive got on

harris hawker said:

Top man, thanks. I will give that a go tomorrow and post how ive got on

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Don't forget to have the ignition on when you ground the wire from the D+

Well today I did the test, the bulb came on when I ground the brown/yellow wire. And on looking I found that connection to not be too good either so replaced that one as well. On refitting I noticed the stud that it fits too was loose, so pulled the alternator out to have a better look, the stud was broken, so now I've striped off the casing and managed to tap out the broken stud, fitted a new bolt in its place and put it back together, to be fair a few nuts were loose, so I thought good things might happen, I was wrong lol, still no battery light. But I've got good readings still on the meter with a number of tests. So looks like I wait till it packs up all together or bite the bullet and buy a new one now to see if this sorts the problem, but it's not cut out at all for the past two days either

harris hawker said:

Well today I did the test, the bulb came on when I ground the brown/yellow wire. And on looking I found that connection to not be too good either so replaced that one as well. On refitting I noticed the stud that it fits too was loose, so pulled the alternator out to have a better look, the stud was broken, so now I've striped off the casing and managed to tap out the broken stud, fitted a new bolt in its place and put it back together, to be fair a few nuts were loose, so I thought good things might happen, I was wrong lol, still no battery light. But I've got good readings still on the meter with a number of tests. So looks like I wait till it packs up all together or bite the bullet and buy a new one now to see if this sorts the problem, but it's not cut out at all for the past two days either

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If the battery light is still not coming on, there is a fault in the alternator. If it's working, it's a degree of luck and residual magnetism that's kicking it into life. You can buy an overhall kit for not a lot of cash, fix it before it strands you somewhere. Sods law say's it will be dark and ****ing down when it happens.

Datatek said:

If the battery light is still not coming on, there is a fault in the alternator. If it's working, it's a degree of luck and residual magnetism that's kicking it into life. You can buy an overhall kit for not a lot of cash, fix it before it strands you somewhere. Sods law say's it will be dark and ****ing down when it happens.

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Overhaul kit sounds the ticket, I never new you could get one, where will I be able to get one from?

harris hawker said:

Overhaul kit sounds the ticket, I never new you could get one, where will I be able to get one from?

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Google is your friend, or Ebay. You need the alternator reference.

Datatek said:

Google is your friend, or Ebay. You need the alternator reference.

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Cheers, I will get the info off it tomorrow and have a look

This morning I set to removing the alternator again to get the part number etc, while I had it off I thought I may as well pull the back off it again to double check I was happy of everything, glad I did!!! The reason for it not working was due to the replacement pin that I used (in this case a bolt) the hex head wasn't meeting the metal and was effectively insulated by the plastic covering that surrounds the hole, out with the dremmel, I ground back the plastic to allow a nice snug fit for the hex head on my new stud, cleaned every contact up, put the lot together again and threw it on!!!
Bingo, job done and works great.

harris hawker said:

This morning I set to removing the alternator again to get the part number etc, while I had it off I thought I may as well pull the back off it again to double check I was happy of everything, glad I did!!! The reason for it not working was due to the replacement pin that I used (in this case a bolt) the hex head wasn't meeting the metal and was effectively insulated by the plastic covering that surrounds the hole, out with the dremmel, I ground back the plastic to allow a nice snug fit for the hex head on my new stud, cleaned every contact up, put the lot together again and threw it on!!!
Bingo, job done and works great.

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Nice one