Ignition Switch Failure??

Discussion in 'Electrical' started by mc2, Oct 13, 2012.

  1. mc2

    mc2 Active Member Contributor

    After 39,940 miles my 08 Fat Boy is letting me down for the first time, and after all I've put it through that's not bad. At least it didn't happen in a remote jungle!

    I've called a shop in the states, but they are now closed till Tue, as well as the Singapore HD till Monday, and I wonder!

    I turned the switch to start, and when I hit the starter button - click.
    All contacts for battery and inside the switch (those three sliders with the springs) are clean, and fuses all ok.

    Battery is at 12.8 v, and if I turn ign. sw. to Accessory there are 12v there, but when I turn the switch to ignition it all drops to 0.3: at the battery, and at the tangs on the ign. sw. Removed the PC V to check with OEM, but nothing different.

    Both shops gave a confirmation that the ignition sw. is probably the culprit. Although there shows continuity on the ign. side of the switch. By appearance the ign. tang (all tangs actually) just run solid through the plastic housing for shared contact by the sliders inside. Puzzling!

    I'm wondering if I can test it by making a direct contact from the center power tang crossed to the ign. tang? Without concern for blowing fuses or worse!
    I'm isolated out in the rice paddys and just want to be careful.
  2. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

    I am not an expert on electrical systems but if the battery voltage across the terminals drops considerably when you press the start button then the battery is faulty and would need to be replaced

  3. eleft36

    eleft36 Junior Member

    IMO if it were the switch you would not even get a click.

    Look at the battery and all the connections to and including all in the fuse panel.

  4. lorne

    lorne Senior Member

    do you have any way of load testing the battery? a simple light bulb should work as a load and see how much the voltage drops once it is connected across + and-.

    BUBBIE Well-Known Member

    CAREFULLY jump start it...IF hooking another small good battery starts it Right up...... BATTERY..

    That would be My bet on the problem as you said the voltage drops off to Nothing when you tried starting and checked battery......:s

  6. Hoople

    Hoople Account Removed

    "there" as in at the switch?
    Where is the important point. You never said exactly where.

    Your meter should be directly at the battery posts.
  7. Jack Klarich

    Jack Klarich Guest

    Check the connection at the starter under the rubber boot, you are in a high humidity are you may have a loose or badly corroded connection, check the ground near the starter also, feel the cables are they heating up?
  8. mc2

    mc2 Active Member Contributor

    I do appreciate all the responses. Thanks.
    Ok, went through the same checks again this morning.
    The three tangs off the bottom of the Ign Sw: Acc., Power, Ign.
    (I have had readings of 12.8 volts directly off the battery).

    With switch off: 10+ volts to Power tang
    Switch at Acc: 10+ volts to Power and Acc tangs
    Switch to Ign:
    1. At times it will go normal (lighting up insturments and headlight) with 10+ volts, but as soon as I hit the start button, it clicks and everything drops to 0.4 v
    2. Most times when turning switch to Ign the insturment (mileage indicator) will flash on briefly, then all is at 0.4 v. (power, acc, ign tangs and battery)

    No jumper cables & have not found substitute, but then would need to find and hand carry a battery back to the bike. Very difficult to get a local to remove his battery!
    Nor found something for a load test yet.
    I have not been able to remove the ground from the starter (the green wire on the forward side). It's a tough location to reach and appears to need a compression to release it, requiring a specail tool as is, or removing the oil tank!

    Checked continuity again from the tangs to the inside of the switch where the sliders make contact and find continuity on all three.
    But in the mystery of electrics, or unknown design, the contact may be just enough for the continuity and that is all.
    When the ign switch is turned on there is a heavy draw off the battery to a direct ground (??)

    The switch does seem suspect, and the shops say they have replaced them because they have failed from excessive vibration (and I've certianly gone through some severe vibrations). But that leads me to assume that between the tang on the outside of the switch and the slider contact on the inside, the connection is not a solid one piece unit within the the plastic mold for the switch.
    And all the other evidence is confusing to me!

    The Tech at the Singapore shop was going to study this and I will talk with him on Monday, and couldn't just sit the weekend without throwing this into the forum.
    I'm sure it's something very simple, but as often, it's difficult to reach that moment of clarity!

    Thanks again for the responses and leads.
    Last edited: Oct 13, 2012
  9. lorne

    lorne Senior Member


    i am guessing that you have a VOM to check the voltage? or do you have a digital dash? as far as a load test a light bulb from any lamp will work (not the best but will give and idea in a pinch) the higher the wattage the better.

    sounds like to live somewhere where i would like to..:D
  10. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

    As Hoople suggested. Try all the measurements you have done except take the measurements at the battery posts. If you are dropping to 10V with the switch on and your headlights and all are working correctly, you do not have enough voltage to get the starter to do much at all.