3 wire alternator wiring - Reply to Topic
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Topic Review (Newest First)

  • 26-03-2013, 23:33
    Good thinking battlecat. I have lost my Jump leads.. need to get some new ones..
  • 26-03-2013, 23:09
    A jump lead will make a good 'portable' lead for temp trying where a good connection works.
  • 26-03-2013, 22:52
    Hmmm yeah I will have a look and see what I can come up with. Now I know it works I guess I can mess around with it a bit and see what will work best!

  • 26-03-2013, 22:27
    Your engine to chassis earth should be OK as most starter motors need a good earth to function correctly so its probably that the alternaor is not earthing through the bracket for some reason, a short cable from the alternator to somewhere on the engine would work equally as well and be neater.
  • 26-03-2013, 22:16
    Batt negative looks a bit greasy but otherwise pretty stout. Same with the engine to Chassis one.. I will take them off and clean them but I think I would rather go straight to the battery from the alternator if possible, just so I know it's sound. I will give everything a good clean though!
  • 26-03-2013, 21:11
    Rather than a long cable to batt negative, have you checked you have a decent engine to chassis earth?
    Also have you got a decent batt negative to body cable.
    Unbolt from body, clean up connections and recheck.
  • 26-03-2013, 18:04
    Look in Yellow Pages under Car Electrics, Phone them up and let them know what you want it for I am sure one of them will be able to help you out and make sure you get the terminals to suit at the same time. I would use a 120/03 size cable, but I am sure they wil supply you with a suitable cable.
  • 26-03-2013, 17:41
    Hmmm odd you should say that as the alternator is in fact from an Astra!

    Ok so I will get a length of cable and run it straight to the battery terminal. Thanks so much for your help! Have you any suggestions where to buy a suitable cable.. I'm assuming it needs to be of a substantial thickness? I am so juiced to finally get it to work! The amp light works on the dash and everything! AWESOME!!

  • 26-03-2013, 17:28
    Ya that is just what the voltage should be. You are right in assuming that it was just a bad earth. I used to have an Astra that had to have the alternator separately earthed. It does no harm running a lead from from the alternator body to the battery - terminal, just the oposite in fact and as it is an earth lead you do not need an inline fuse. I have just emailed Lucas to find out what the other 2 terminals are for, will let you know when I get a reply. Glad that you have finally got it sorted.
  • 26-03-2013, 16:55
    Ok so I rushed out and checked before this got posted ^^

    Just by connecting a sketchy cable from the alternator body to the battery negative I got an increase up to 13.18 volts! That's with a lump idle as well.. I let the choke out a little bit just to increase the revs and it went up to 14!

    This is good yes? Should I still perform the checks listed by brading? I'm assuming that one way or another I have a bad earth somewhere along the line.. and by assume I mean you guys told me! So is it a bad thing to always run the alternator body to the battery? Obviously with a nice new cable.. maybe with an inline fuse?

    How should I proceed?

    Thanks loads to everyone!!
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