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Thread: 88 K75C stolen, recovered - ignition switch torn off and now wont start

  1. #1

    88 K75C stolen, recovered - ignition switch torn off and now wont start

    My 1988 K75C was stolen from out of my apartment building's garage. They didn't get it very far and I found it parked a few blocks away having been dropped on its right side and the ignition switch ripped off.

    I ordered a replacement ignition switch, wired it up and replaced all fuses but I'm not getting any lights on the cluster, no clicking of relays, and it wont start. I removed the seat and shimmied the fuel tank up a bit to get some access to the electrical box - Thus far, here's what I know:

    1. Clock works
    2. No headlights or bulbs on the cluster
    3. There's 12.7v+- across fuse #5
    4. There's 12.7v+- on the positive side of the starter relay
    5. There's nothing on the red 12v line (or any of the other lines) on the 4 wire connector that goes to the ignition switch

    I've been reading MOA and looking at the wiring diagram trying to figure out what/where the culprit could be and I'm not sure if I should be looking at the starter relay, starter motor, broken wire somewhere further towards the electrical box from the connector under the tank or what.

    Please help!
    Last edited by nullfox; 07-09-2020 at 12:57 AM.

  2. #2
    3 Red Bricks
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    Kill switch?



    LONG MAY YOUR BRICK FLY!

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    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
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  3. #3
    Disassembled and cleaned the kill switch per your instructions here: https://forums.bmwmoa.org/showthread...rt-Kill-Switch

    After I cleaned it and still had the switch off the bars, I used my multimeter to check for current on the contacts on the back that the button itself actually touches and there's nothing there.

  4. #4
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    Sorry for my not well thought out responce earlier. I was sidetracked by a bunch of non motorcycle things at the time.

    The power goes from the poitive side of the battery to the positive side of the starter relay (large red wire terminal 30).

    There should be another red wire on the same terminal. This wire should go to a cluster of 6 red wires somewhere inside the relay box. Three of those wires go to fuses 3,4, and 5. Check for power at each of those fuses. Another of the six wires go to the load shed relay. The sixth wire goes straight to the connector for the ignition switch with no interuptions.

    Find that cluster and follow the wires. If all six wires are connected together and you have power to fuses 3,4,and 5 and have power to the load shed relay (terminal 87), then the break is between the ignition switch connector and that cluster of red wires in the red wire to the ignition switch. That wire is in the main harness under the tank. Use an Ohm meter to check continuity between the wire cluster and the ignition switch connector. If they pulled hard enough on the switch wireing the may have broken the wire in the connector.



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  5. #5
    3 Red Bricks
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    Sorry for my not well thought out responce earlier. I was sidetracked by a bunch of non motorcycle things at the time.

    The power goes from the positive side of the battery to the positive side of the starter relay (large red wire terminal 30).

    There should be another red wire on the same terminal. This wire should go to a cluster of 6 red wires somewhere inside the relay box. Three of those wires go to fuses 3,4, and 5. Check for power at each of those fuses. Another of the six wires go to the load shed relay. The sixth wire goes straight to the connector for the ignition switch with no interuptions.

    Find that cluster and follow the wires. If all six wires are connected together and you have power to fuses 3,4,and 5 and have power to the load shed relay (terminal 87), then the break is between the ignition switch connector and that cluster of red wires in the red wire to the ignition switch. That wire is in the main harness under the tank. Use an Ohm meter to check continuity between the wire cluster and the ignition switch connector. If they pulled hard enough on the switch wireing they may have broken the wire in the connector.



    Last edited by 98lee; 07-17-2020 at 08:22 PM.
    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
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  6. #6
    MOA #24991 Pauls1150's Avatar
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    Maybe it's just the choice of words, but symptom #3 would mean that the fuse is blown.
    Putting a voltmeter "across" a fuse should show Zero or very close to it.

  7. #7
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    Paul,

    The power to the ignition switch does not go through a fuse.

    Fuse 3 controls the clock, turn signals, and the flashers.






    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  8. #8
    MOA #24991 Pauls1150's Avatar
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    Thanks Lee, so it's not a root cause... still seems odd, though...

  9. #9
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    Quote Originally Posted by Pauls1150 View Post
    Thanks Lee, so it's not a root cause... still seems odd, though...
    I think (like you suggested) that it was just semantics. He probably meant that he had 12volts (to ground) at both sides of the fuse.





    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  10. #10
    Apologies, that was poor phrasing on my part.

    98lee has it right, I have 12v to ground on both sides of the fuse.

    Also, thank you 98lee for the write up on the red wire cluster - I'm going to pull the tank all the way off and go through the bundle as you describe to hopefully find the wire break somewhere.

    Cheers

  11. #11
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    Quote Originally Posted by nullfox View Post
    Apologies, that was poor phrasing on my part.

    98lee has it right, I have 12v to ground on both sides of the fuse.

    Also, thank you 98lee for the write up on the red wire cluster - I'm going to pull the tank all the way off and go through the bundle as you describe to hopefully find the wire break somewhere.

    Cheers
    You might want to look very closely at the connector that the ignition switch harness plugs into first. That is probably the most likely area to have been damaged by the theft.



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  12. #12
    Quote Originally Posted by 98lee View Post
    You might want to look very closely at the connector that the ignition switch harness plugs into first. That is probably the most likely area to have been damaged by the theft.
    I haven't had a chance to do the full red wire tracing, but the other day when I lifted the tank, I did check each wire for current in the female side of the ignition switch plug coming from the harness and there was nothing which makes me think as you originally posted, it's closer to the big bundle of red wires.

    Cheers
    Last edited by nullfox; 07-10-2020 at 05:30 PM.

  13. #13
    It's alive!

    Thank you all for your help, in particular 98lee.

    I traced the bundle of 6 reds, everything had current inside the relay box. I traced the red wire up and found that the male pin inside the ignition switch connector didn't have current, but the wire going into the back of it did. I ended up replacing the entire connector with a new Deutsch connector and things are all good now.

    The only other thing to resolve is that the thieves dropped the bike on its right side and I think it pushed the bar end mirrors I installed too far in and is causing the mirrors to interfere with the throttle which is now a little sticky/too much friction, but that should be relatively easy to resolve.

    Cheers and thanks again for the help y'all.

  14. #14
    3 Red Bricks
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    I love happy endings!!!

    (Not THOSE kinds. You perverts!)



    Thanks for getting back wth the results.








    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

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