'01 Fatboy Electrical Problem

Discussion in 'Electrical' started by skinautique1993, Mar 7, 2009.

  1. skinautique1993

    skinautique1993 New Member

    Battery on tender, when I went to start it for my first ride this season, nothing. I put it on the big charger for 30 minutes, fired it up and rode for 30 miles, shut it off, won't re start. I took the battery to my local dealer to have it checked, after charging all day, it had 7 CCA. OK got new battery. During installation, I noticed a draw on the battery so I started checking things, yep got one. I check between the neg. post and the neg. cable for verification. In my ski boat, I could isolate the diode trio set to duplicate the draw.
    In your great article on this subject, you reference the two wire regulator during troubleshooting the system. I have a three wire regulator. Is there info on the site that would tell me the same info? Also, if I'm testing the system for draw, and I unplug the regulator and the draw goes away, does that tell me anything besides the regulator is unplugged.

    Thanks for any help you may have.

    NEWHD74FAN Experienced Member Retired Moderators

    Welcome to HDTalking...attached below is a link to help troubleshoot your charging system. If you have a copy of the Service Manual ($60) at the HD, a multi-meter (digital is easier and at Harbor Freight $9) and careful not to cross or ground connections or probes you should be fine. There may be a PDF of the electrical system, I am just having trouble finding the exact link...so far...


    Found link to schmatics, latest 1993 GIF should work:

    1965 - 199x Harley Davidson Wiring Diagrams - HD Talking Downloads Page - Harley Davidson Community

    For finding where the "sneak" leakage current is, in the schematic, there are 3 paths, 2 easily isolated...the protective fuse, and the relay...if not a bad diode in the alternator (not as easy), I would start with likely path being the relay...as it is designed to isolate low current control path from high current switching path...good luck
    Last edited: Mar 7, 2009
  3. krikket

    krikket Active Member


    From what I remember, you can check the diodes in the alternator by setting your meter to read AC volts, start up the bike and measure voltage across the battery. If you get a reading over 0.5 volts, you probably have a bad diode.
  4. potato

    potato Member

    The voltage regulator junctions with the ign. switch @ the main circuit breaker located behind the fender ext. they junction together on the silver stud the red is ign. and the black is the voltage reg.
    good luck.