2000 softail blowing fuse, ground issue?

Discussion in 'Electrical' started by AsphaltJunkie, May 9, 2012.

  1. AsphaltJunkie

    AsphaltJunkie Member

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    2000 fatboy, 88ci/carbed/no mods... speedo/odometer started cutting out, cleaned speed sensor. Started doing it again so I thought voltage regulator. Unfortunately she died before I got her home. Bike backfired and shut down on the road. No power at all. Accessory fuse blown, battery hotter than the oil tank. Now she has a new voltage reg, battery, main circuit breaker and starter relay but whenever I turn the ignition switch the acc fuse blows... badly. You can hear the pop and see the flash. We went over the wiring harness and can't find a short or loose ground anywhere. The speedo runs on the acc circuit so I can't get codes if there are any. My indy passed away a few months ago and the dealership is last resort so any suggestions would be greatly appreciated. Btw I bought it in Feb 09 from the original owner and have never had any problems with her. Thanks again
     
  2. Hoople

    Hoople Account Removed

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    The Accessory fuse feeds a bunch of things. The speedo, turn signal module, left & right turn signal switches, horn, both Front & Rear stop light switches and the rear brake light.

    Remove the ACC fuse. The accessory fuse holder should have an Orange/white wire going to one side. Leave the ignition key in the OFF position.
    Take you ohm meter and place it in the 200 ohm scale. Don't use auto-ranging.. because it will drive you crazy. Clip the meter between the Orange/white wire of the fuse holder and frame ground. You should read near Zero ohms.

    While watching the meter, disconnect the speedo connector and see if meter pops up with a higher reading. If not (stays near zero), leave the Speedo disconnected and now disconnect the turn signal module. Meter pop up? If no, leave those connectors disconnected and remove the tail light bulb...
    Sooner or later the meter will pop up which will indicate to you where the short is. My guess is the speedo or turn signal module may be bad. If disconnecting those units don't lift you from the short, check back and I will walk you through the steps.

    Do you have a shop manual or schematics?
     
  3. AsphaltJunkie

    AsphaltJunkie Member

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    Yup acc fuse showed 0, lights ignition and gauges all showed 5+. I'll run through those tests when I get home tonight. I have the HD service manual, it has the wiring schematics in the back.

    Thank you
     
  4. AsphaltJunkie

    AsphaltJunkie Member

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    Wife just reminded me that the hazard lights didn't work either. I always thought they ran off the battery circuit but I guess the signal module still controls them? May have to check that first

    sent from my R2-D2 using the force
     
  5. Hoople

    Hoople Account Removed

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    That sounds about right. If you check the other branches or fuses as a reference, be sure to have the fuses removed otherwise all the readings will be the same value which is incorrect.
     
  6. AsphaltJunkie

    AsphaltJunkie Member

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    Well I pulled the TSM connector and ohm meter went to 51. And my speedo works again. Will see if I can get my hands on a new one tomorrow.

    I can't thank you enough for the help Hoople

    Sent from my ADR6350 using Tapatalk 2
     
  7. Hoople

    Hoople Account Removed

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    It is probably the Turn Signal Module itself, but before you buy a new one that you can't return I would cross check my work by taking your ohm meter and measuring between pin #1 (ground) and pin # 2 (power) of the module itself (not the wiring harness). You should find a dead short which would conclusively tell you the module is bad.

    Pin #1 is where a black wire would go.
    Pin #2 is where a orange/white wire would go.
     
  8. AsphaltJunkie

    AsphaltJunkie Member

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    I saw this too late... but you were right. Not blowing fuses now, all lights and signals are working now (except tailight, probably a bulb) and the speedo lights up. Only problem now is the engine light isn't coming on when I hit the run switch. The motor turns over, got good compression, just no spark. Checked coil, plugs, wires, all good. Ignition module maybe?
     
  9. Hoople

    Hoople Account Removed

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    Unless you boosted the bike with a roll around battery charger or your regulator was running wide open without any regulation, it would be very unusual to have 2 blown modules. There are a few basic things you may want to check before replacing the module. Inspect both connectors going to the ignition module. Remove, inspect & re-install both connectors. Try engine again. If no spark then you may want to check the following 3 items. Power to the coil, the crank sensor and the cam sensor.

    1) There is a white w/ black wire going to terminal "B" of the coil. Check to see if there is battery voltage on that wire during engine cranking (with kill switch in the RUN position). You should see battery voltage on that wire during cranking.

    2) Locate the crank sensor in the lower engine block. Disconnect the crank sensor from the wiring harness. (connector # 79). Remove both spark plugs.
    Connect your voltmeter across the 2 crank sensor terminals. Place your volt meter in 20 AC scale. While cranking the engine, do you read at least 2 volts AC.
    Be sure your meter is reading AC volts.

    3) To check the cam sensor, locate the Ignition module. There are 2 connectors going to the ignition module. One is gray and the other is black. Each connector has 12 pin positions. On the Gray Connector, pin # 1 has a Red w/ white wire. Pin # 3 has a Green with white wire going to it. Pin # 8 has a Black w/ white wire going to it. Lift the rear wheel off the ground and place the engine in 5th gear. Place your voltmeter in the 20 Volt DC range. Connect your volt meter across Pin # 8 (negative) and Pin # 3 (positive). Turn On the ignition with kill switch in RUN position. Rotate the rear wheel by hand and watch the meter. The meter should go from appox +5 volts to Zero volts, then back to 5 volts then to zero volts ,,, over & over again. That is 5v,0v,5v,0v,5v,0v,5v,0v.....
    Because the ignition module supplies the 5 volt reference, the module must be hooked up while performing this test. You must back probe the connector with your meter.

    There's more, but I would be surprised if you passed all 3 tests.
     
  10. AsphaltJunkie

    AsphaltJunkie Member

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    Nah I have a small Deka motorcycle-specific charger. I was running between 55-60 when it went out. I pulled the crank sensor and it was clean, no metal on the magnet, but I didn't check the voltage. I did check the W/Bk wire to the coil and got 12+v. Someone suggested checking the voltage on the #10 pin on the black connector to the ign module with run switch on and only had .4 volts. I was thinking ignition module cause the Engine light doesn't come on when I hit the run switch. I'll run those tests tonight. Thanks again