alternator / charging

Jake the Peg Jul 8, 2019

  1. Jake the Peg

    Jake the Peg Well-Known Member I am in scotland

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    Today I fitted a new alternator in the hope that the dash warning lights Christmas tree would go out, but no luck, So some further checking, with the supplier, and fluke, I should see 12 v on all 3 wires on the alternator loom, but I don’t see any voltage on the white wire (battery voltage) if I bring 12v to the white wire I see 14.2v and a nice dark dash panel, so I assume I have a break in the white wire somewhere, charge fuse is ok..

    I seem to remember reading about someone else finding the broken wire, but I can’t seem to find the post again, so before I start pulling things apart, can anyone point me in the right direction, yes it could be broken anywhere but no harm checking where someone has found it before!

    Thanks

    J
     
  2. Jake the Peg

    Jake the Peg Well-Known Member I am in scotland

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    Rather than be totally lazy, I decided to just get a move on and start chasing the wiring, I found the white wire that connects to a small junction box then up to the passenger battery+ snapped had dropped down below the 24v starter gizmo, so an easy fix, all the dash warning lights out and a nice steady 14.2v charge over the batteries

    Next job steering box seals.....
     
  3. Dave 2000

    Dave 2000 Well-Known Member Supporter I am in spain

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    I had exactly the same problem, it is the battery voltage sense wire, it is white in a black sheath. I just replaced my VSR and found that wire had corroded where it connects to an insulated body mount. I must have disturbed it as I only had the problem after working in that area, I cut out the connector and run a new wire to the VSR, the type of problem you might get if out on a rough road miles from the 'Grua'. :icon-wink:

    Glad you found it.

    regards

    Dave
     
  4. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    The short broken wire was almost certainly a fusable link. It should be replaced with same or have a fuse spliced in immediately it leaves the battery terminal else fire could result if the alternator goes bad or if a short is presented on that wire. A 10A fuse should be ample but needn’t be that big as it only senses and doesn’t actually draw current.
     
    clivehorridge and Jake the Peg like this.
  5. Dave 2000

    Dave 2000 Well-Known Member Supporter I am in spain

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    Hmmm could be crossed wires (no pun intended)., the wire I am talking about used to be connected to the 12/24 changeover relay. If disconnected the starter does not crank, and if it did crank and start then the dashboard lights up like a Christmas tree as the alternator goes over voltage. The fusible links on mine have been changed for proper fuses and it took awhile to work out what went where, and IIRC (long while ago) neither of the two were connected to the alternator voltage sense so............?

    regards

    Dave
     
  6. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    .....there is a voltage sense wire through a fusible link. I think we probably posted at the same time Dave, as I was replying to Jake’s post about the white wire, through a little black junction box.
    Crossed posts more than crossed wires perhaps? :)

    Jake’s wire I was referring to

    433E9F0C-3EE0-41E6-9C60-B255E88CAB40.jpeg

    I suspect to be the wire you are referring to is circled below Dave?

    56500D4B-3B98-4416-983F-0097DECB401C.jpeg
     
  7. Dave 2000

    Dave 2000 Well-Known Member Supporter I am in spain

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    Thanks for taking the effort to post up. I need to get better glasses as I cannot see the diagram too well, does that diagram at the top show three FL's, I only had two on mine and replaced them with fuses. And yes the lower diagram with the red circle is in about the right place, that wire is white but inside a black sheath. I tried zooming in but the clarity goes, can you see what colour is shown on the diagram?

    regards

    Dave
     
  8. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    It’s not easy to see I’ll grant you Dave. Try these.
    3FB60D45-345C-4E9B-9EF7-4C92888FD5AA.png 5F87C784-264A-441C-8668-FEF46B4B81CB.png

    I think it means there are only 2 fusible links with the left hand one (shown on the battery marked RH) being either or. So the Alternator connection either goes through two fusible links outside Europe or has no fusible link and links direct to the LH battery for Europe models (I think that’s it!). Whatever happens, there should be the volt sense wire going to the LH battery in your case through a fuse. Outside Europe, it connects to the 50A AM1 fuse.

    B30CDC23-FDBA-4938-90F9-50C9457924D3.png

    Two possibilities then, your truck has been altered (during your 12v start conversion) or it is a non European model.
    Or the wire is disconnected somewhere.
     
  9. Dave 2000

    Dave 2000 Well-Known Member Supporter I am in spain

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    No idea mate, the 12v conversion meant no reason to never touch fusible links near the battery. As per my earlier post, the only white wire I had near the 12/24 changeover switch had some corrosion it was cut out and a new connector fitted. Mine does have a UK spec, having traced it's origin it came into Britain via Ireland in 1994 so.......?

    At the moment I am having some health issues which makes concentrating on stuff difficult and I am short on patience, when I get over this I will sit down and find the scribbling's I made years ago, they may shine some light on the subject.

    regards

    Dave
     
  10. frank rabbets

    frank rabbets Well-Known Member

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    Get well soon Dave.
     
  11. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    :text-+1:
     
  12. Dave 2000

    Dave 2000 Well-Known Member Supporter I am in spain

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    Coming out of the woods now guys, appreciate the comments. :thumbup:

    Not looked through papers yet, but will soon. I have made a tentative return to light duty part time work, most of my work having been farmed out to a local garage. So a gentle three mornings a week ATM.

    regards

    Dave
     
  13. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    Glad to hear you’re on the mend. :clap:
    Hope you’re back to full fitness soon.
     
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