CHOP CULT HOME
Email Password
Search
  1. #1

    Join Date
    May 2022
    Posts
    8

    Default Sportster Ignition Fuse Blowing

    I have a 2003 XLH1200 that I hard-tailed. I used the factory wiring harness, just shortening some wires to fit the new frame. I reassembled everything and the bike worked well. I disassembled it for paint and reassembled again, looming the wiring. When I hit the start switch, the 15amp ignition fuse blew. I have removed all the loom to expose the wires and check for a short, but cannot find one. The fuse blows when the starter relay is connected. If I remove the relay, pressing the start switch does not blow the fuse. I used a multimeter and checked the wires from the switch to the relay socket and they all check out fine. Checking each of the wires from the controls to ground, I have no continuity, the needle on the ohms meter stays at the highest end, not moving. This tells me I have a problem with, or after the starter relay. I put another, used but working as far as I know, relay in and the fuse blows when I press the start switch, just like the other relay. Checking the wires in the relay socket to ground, I get no continuity between ground and the black/red wire coming from the starter switch to the starter relay. I get a 0 ohms reading from ground to the green wire that goes to the starter motor. I see no nicks, etc on the wire so I think it is ok. I don't know what to do next to diagnose the problem...

  2. #2
    Senior Member

    Content on this page requires a newer version of Adobe Flash Player.

    Get Adobe Flash player


    Join Date
    Dec 2018
    Posts
    2,322

    Default

    Sounds like the green wire from relay to solenoid is grounded. Or the solenoid is shorted to ground internally. Disconnect the solenoid and try the start button again. You are on the right path to figuring this out.

    Jim

  3. #3

    Join Date
    May 2022
    Posts
    8

    Default

    Thanks, Jim. I was thinking it sounds like the green wire , but it appears fine. Maybe it is internal. will take a closer look at it tonight.

  4. #4

    Join Date
    Mar 2022
    Posts
    128

    Default

    Make sure your front end/handelbars are grounded properly.
    I always run a separate ground to the riser bolts from the frame.

  5. #5

    Join Date
    May 2022
    Posts
    8

    Default

    Quote Originally Posted by JBinNC View Post
    Sounds like the green wire from relay to solenoid is grounded. Or the solenoid is shorted to ground internally. Disconnect the solenoid and try the start button again. You are on the right path to figuring this out.

    Jim
    The green wire going to the solenoid is fine. To be sure, I disconnected the green wire from the solenoid and the relay plug so it wasn't even in the equation. I reconnected the relay, turned on the ignition, and when I pressed the start switch the fuse blew. Now I know it isn't the green wire or the solenoid, but I still can't figure it out.

  6. #6

    Join Date
    May 2022
    Posts
    8

    Default

    Quote Originally Posted by SteveJ View Post
    Make sure your front end/handelbars are grounded properly.
    I always run a separate ground to the riser bolts from the frame.

    Thanks, Steve. I don't think a fuse would blow from a lack of ground, it just wouldn't have power as the circuit wouldn't be complete. Of course, I could be wrong. Also, when I had the bike running before disassembling for paint, I didn't have a separate ground then and everything worked properly.

  7. #7

    Join Date
    Mar 2022
    Posts
    128

    Default

    Quote Originally Posted by GCUT519 View Post
    Thanks, Steve. I don't think a fuse would blow from a lack of ground, it just wouldn't have power as the circuit wouldn't be complete. Of course, I could be wrong. Also, when I had the bike running before disassembling for paint, I didn't have a separate ground then and everything worked properly.
    I was assuming you had switches on the handlebars.Weird stuff can happen without the handlebar ground.
    If you dont have this ground then this is an opportunity to complete your wiring harness , in my wiring harness work there are usually 3-4 dedicated grounds as on stock bikes.
    Sketchy grounds make components work harder , making electrical components work harder means more heat , more heat means fuses/breakers blow.
    Good luck!

  8. #8

    Join Date
    May 2022
    Posts
    8

    Default

    Quote Originally Posted by SteveJ View Post
    I was assuming you had switches on the handlebars.Weird stuff can happen without the handlebar ground.
    If you dont have this ground then this is an opportunity to complete your wiring harness , in my wiring harness work there are usually 3-4 dedicated grounds as on stock bikes.
    Sketchy grounds make components work harder , making electrical components work harder means more heat , more heat means fuses/breakers blow.
    Good luck!
    I am running the stock controls on the bars. I am going to try adding a separate ground from the riser bolts to the frame like you suggested and see what happens. I appreciate your input greatly, Steve!

  9. #9

    Join Date
    Mar 2022
    Posts
    128

    Default

    Quote Originally Posted by GCUT519 View Post
    I am running the stock controls on the bars. I am going to try adding a separate ground from the riser bolts to the frame like you suggested and see what happens. I appreciate your input greatly, Steve!
    Its not gonna hurt!

  10. #10

    Join Date
    May 2015
    Posts
    643

    Default

    Quote Originally Posted by SteveJ View Post
    Its not gonna hurt!
    Ill bet its in the handlebar controls. Most likely a wire pinched or frayed, especially where the controls pinch against the handlebars and the harness passes thru

  11. #11

    Join Date
    May 2022
    Posts
    8

    Default

    Quote Originally Posted by docmel View Post
    Ill bet its in the handlebar controls. Most likely a wire pinched or frayed, especially where the controls pinch against the handlebars and the harness passes thru
    That is the most common cause, but I am confident it is not that. I have had the controls off and inspected and all the wires look good. Then I used the multimeter to check for conductivity with ground on each wire individually, and also while pressing the start switch. That checks out fine. Since the fuse doesn't blow until the start switch is pressed, and the relay is on, that has to indicate something, but I haven't been able sort it out yet.

  12. #12

    Join Date
    Mar 2022
    Posts
    128

    Default

    Its not the ignition fuse thats blowing if it happens when you press the start switch.
    Its the starter circuit fuse which is actually a circuit breaker most likely, to use the correct terms.
    Ignition and starter circuits are 2 seperate circuits , the only connection is that the starter switch gets its power from the ignition kill switch in the right handlebar switch cluster.

  13. #13

    Join Date
    May 2022
    Posts
    8

    Default

    Quote Originally Posted by SteveJ View Post
    Its not the ignition fuse thats blowing if it happens when you press the start switch.
    Its the starter circuit fuse which is actually a circuit breaker most likely, to use the correct terms.
    Ignition and starter circuits are 2 seperate circuits , the only connection is that the starter switch gets its power from the ignition kill switch in the right handlebar switch cluster.
    It is labeled "Ign. 15A" so that's why I say it is the ignition fuse. There are four fuses on the bike: Ign, Instr, Lights, and Acc. All are 15 Amp. The main circuit breaker that runs a lead to the starter solenoid is 30A and isn't the problem. I'm still working on it, but I'm stumped. The Red/Blk wire in the starter relay plug that goes back to the ignition switch reads 0 ohms when checked with ground. This seems wrong to me. I don't think it should have continuity with ground, but I have the wiring completely exposed now and cannot see any cuts, breaks, nicks, etc.

  14. #14

    Join Date
    Mar 2022
    Posts
    128

    Default

    I just had a look at a schem diagram for this bike , pretty easy to read and very few wires in the circuits you are working on.

  15. #15

    Join Date
    May 2022
    Posts
    8

    Default

    Quote Originally Posted by SteveJ View Post
    I just had a look at a schem diagram for this bike , pretty easy to read and very few wires in the circuits you are working on.
    Yeah, I agree it looks simple. That's part of why it is so frustrating...

Share This



Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Log in

Log in