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120 c john deere

Ron Novak ยท 2019-02-01 13:31

I have a John Deere 120c that my alternator is not charging . The exciter wire to the alt. isn't working . Does anyone now if there is a fuse in that wire and if so which one it might be . I can't find a wiring schematic for the alt.system i pulled the cover off behind the seat and there is a lot of fuses behind the seat .

Replies5
  1. #1mg23612019-02-01 18:59

    The excitation wire should just be a jumper from the B+ terminal to the D+ through a resistor.

  2. #2John C.2019-02-01 21:00

    All those I've looked at over the years were self exciting. The extra wires performed other functions that had to do with the computer. A wiring diagram is a must.

  3. #3mg23612019-02-02 05:23

    See attached.

  4. #40072019-02-02 06:43

    The alternator does not require an exciter wire. The resister is often on the inside of Alt. If the alternator is not faulty the current to excite the alternator comes from the B+ terminal when K14 pulls in from the ignition switch. Have you checked 24V+ appears on B+ when ign turned on?

  5. #5Ron Novak2019-02-03 08:23

    Thanks that is what i needed . i ordered that resister and that should take care of the issue .