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Thread: Alternator wiring questions 71 911T

  1. #1
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    Cool Alternator wiring questions 71 911T

    In wiring the Motorola alternator...I am in the dark on this one....I have run into conflicting documentation. I did not take the engine apart and no pictures or supporting documentation to assist. So...want to assemble on the side of caution and insure that I make the appropriate connections to the alternator. I have the following wires and colors and connections as indicated in the Haynes manual.
    B+ 1 RED large wire no problem this is larger red wire
    DF 2 Black no problem this is a spade connector
    D_ 3 Brown wire no issue
    D+61 RED I have a blue wire...and not clear exactly where it connects....does anyone have a picture or diagram

    Also not clear as to where to connect the alternator ground wire on alternator and on the case... any pictures or clarification greatly appreciated.

  2. #2
    The terminals are marked on the alternator.
    Early S Registry member #90
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  3. #3
    Senior Member ThomasTe's Avatar
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    Name:  IMG_8519 (Medium).jpg
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    And run a ground wire from the fan housing/alternator mounting nut to the engine case.
    Thomas
    1973 911S Targa

  4. #4
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    As I think about it (slept on it)...I believe that the brown wire is the ground and the alternator terminal for ground is labelled D-. Is that correct...?

  5. #5
    Senior Member M_deJong's Avatar
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    Yes. The picture above shows it clearly. There should also be a braided ground strap from the housing to the engine case.
    Mike de Jong | '71 911T/E 2.4 Tangerine | '74 911S 3.2 Ice Green

  6. #6
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    Here is another picture showing the alternator connections. As for the ground strap to the engine, that was only needed on later alternators with the internal regulator. Early cars don't need it.
    Name:  Alt 73.jpg
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    E Sully
    1973.5 911T

  7. #7
    Hate to disagree here Mr. Sully, but I believe they all got the ground strap irregardless. I always put one on, can't hurt to insure good grounds.
    Early S Registry member #90
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  8. #8
    member #1515
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    Having recently done this on my 73 with Sev/Marchal, there are 2 ground straps, one at the rear braided and one of the rear fan air vanes going to the fan housing.
    Attached Images Attached Images  
    David

    '73 S Targa #0830 2.7 MFI rebuilt to RS specs

  9. #9
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    Quote Originally Posted by edmayo View Post
    Hate to disagree here Mr. Sully, but I believe they all got the ground strap irregardless. I always put one on, can't hurt to insure good grounds.
    Edmayo is correct.
    Last edited by ESully; 08-30-2014 at 11:42 AM. Reason: Found info
    E Sully
    1973.5 911T

  10. #10
    Member #226 R Gruppe Life Member #147
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    +1 for Ed. I've rebuilt so many engines I can't keep track, all early engines had braided ground strap from bottom stud of alternator, thru fan housing, connected to one of the top engine case studs. Gled

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