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XJ650J Tach and Dash Lights Not Working

Discussion in 'XJ Technical Chat' started by Dan Gardner, May 6, 2022.

  1. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

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    I removed the instrument cluster before winter and cleaned it up and lubed the speedo over winter.

    The good news is that with a new speedo cable and a cleaned an lubed speedo clutch, the speedo now is as smooth as butter.

    The bad news is that my tachometer and the "dash" lights are no longer working. All other lights work just fine. Bike runs just fine. Brake lights, turn signals, horn, warning lights, all fine. Just the two bulbs that light up behind the speedo and tach and the tach itself not working.

    The fact that the cluster was fine last fall, I had the cluster out over the winter and now there is a problem means that there is a really good chance that I messed something up.

    I'm not sure if I'm dealing with one problem or two.

    Here's what I've looked at so far:
    • Any wires I forgot to plug in in the headlight bucket? Nope, all the non-used connectors seem to match the wiring diagram.
    • Fuses? They all checked out.
    • Bulbs? They all check out fine
    • Headlight relay? Tried a different one with no difference (this may have been grasping at straws)
    • TCI not sending signal to tach? Maybe, but TCI works well enough so that it runs fine
    Would there be a poor ground somewhere that could effect the tach and dash lights but nothing else?

    What's my next move?

    Thanks
     
  2. XJ550H

    XJ550H Well-Known Member Premium Member

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    dash lights try changing the bulbs.
    it is a simple circuit
    meter lights.png
     
  3. Rooster53

    Rooster53 Well-Known Member Premium Member

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    Most likely since the non functioning tach uses a different 12V source than the indicator bulbs but shares the ground

    It is easy to prove, just go inside the headlight bucket and find the tach 4 pin connector and the speedo 3 pin connector. Check the black wires for continuity to the frame - they should be shorted

    High beam indicator and auto cancel working?
     
    Last edited: May 7, 2022
  4. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

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    High beam indicator - tested, NOT working. Should have tested that before.

    T/S auto cancel: tested, appears to NOT be working. I drove around like a bonehead with a turn signal flashing for a while and it never stopped.

    Looking at the schematic, it looks like they share the black ground, so that's a good bit of data. But other things seem to share the black ground that are working (flashers and tail light), which confuses me.

    Do I assume there is a continuity problem with the black ground somewhere and start doing continuity checks at all the endpoints where the black wire goes?
     
    Last edited: May 7, 2022
  5. XJ550H

    XJ550H Well-Known Member Premium Member

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    all the grounds are black in the wiring diagram it just shows everything going to the same wire for ground .
    it is likely that the ground wire in the connector is not making good contact to the mating connector

    test ground from bulb socket as it is the end of the line if bad cheak from connector to main harness. then check from tach connector to bulb socket
     
  6. jayrodoh

    jayrodoh YimYam Premium Member

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    I didn’t see it mentioned, is the headlight working? If so it almost has to be some ground connection as that is needed for the lights and the reed switch for the canceling unit. All located in the cluster.

    Did you check the ground at the harness like @Rooster53 asked? Definitely next step there. Just because the blinkers and tail light work does not mean the cluster is grounded, same wire in circuit but doesn’t mean there is continuity from the harness main ground connection to all the other connection points.
     
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  7. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

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    Headlight high and low beam works.

    I checked and cleaned up ground points at the coils and right under the rectifier.

    Continuity of the black ground wire doesn't seem to be the problem - I can put 12V just about anywhere on the frame and read 12V at those ground wires in the bucket, which tells me the black wire in the bucket is grounded to the frame.

    To add insult to injury, I somehow managed to wreck the TCI as well. Only runs on 1 and 4 now. I swapped over the TCI from a 750 for a second and it ran fine, so really seems like TCI is cooked now.
     
  8. Rooster53

    Rooster53 Well-Known Member Premium Member

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    Huh? What do you mean you can put 12V on the frame? An open ground wire is going to measure battery voltage if you reference it to ground (the frame).

    Go back to checking continuity at those black wires for the circuits that are not working, like stated before they should ohm a short to ground.

    Every one of those dots you see on the schematic is not exactly how it is built, but it does represent a splice point either at a crimp or at wires doubled up in a connector. It is not hard to imagine how an open in one of those could cause your issue.
     
  9. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

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    To test the continuity of the black (ground) to frame, I made a simple circuit using a battery:
    Battery -> frame -> ground wire in bucket -> DMM -> back to battery.
    That circuit tells me the black ground wire in the bucket has continuity to ground.
     
  10. Rooster53

    Rooster53 Well-Known Member Premium Member

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    So did the tach work then?

    OK, but I thought that was what the battery in the DMM was for :)

    So maybe you do have a 12V problem, kind of depends on if the tach worked with the other TCI

    If so, go to voltage mode and just check the power at the respective connectors - got 12V, got ground, must me a bad bulb or bad meter harness

    Start the bike up and stall it with the sidestand so the headlight relay will stay energized to check the 12V, or bypass the headlight relay to get the 12V, or energize the headlight relay by momentarily applying 12V to the appropriate AC Generator pin

    ....but headlight works and that voltage is used to power the headlight indicator bulb - so back to missing ground, bad bulb???
     
  11. chacal

    chacal Moderator Moderator Supporting Vendor Premium Member

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    This is absolutely correct, and there is more than one "harness ground" on the bike. The one at the rear coil mounting bolt is one, there is another one by the regulator/TCI mounting, and on some bikes a third "harness ground wire to frame" mounting point.

    How did u fry the TCI?
     
  12. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

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    No. Still no worky. Maybe the tach is bad???

    Either my el cheapo DMM doesn't do that or I don't know how to use it. Most likely the latter.

    Where would this be? I've only found the one on the coil mount and one under the rectifier so far - and not counting the engine to battery wire.

    Not sure. My best guess is that maybe I started the bike with a ground disconnected??
     
  13. XJ550H

    XJ550H Well-Known Member Premium Member

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    1 or 2 grounds at ignition coils.

    there is a ground from motor to frame left side if i remember correctly
     
  14. jayrodoh

    jayrodoh YimYam Premium Member

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    That bike only has one ground for the harness from the factory.

    Tach not working is another indicator of a missing ground to the gauges and lights.

    Have you checked ground at the actual connections in the bucket for the cluster?
     
  15. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

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    Yes, I think so. I made this simple circuit:
    Battery -> frame -> ground wire(s) in bucket -> DMM -> back to battery.
    And it read 12V.
    Which to me indicates that I have continuity from the ground wires in the bucket to the frame.
     
  16. jayrodoh

    jayrodoh YimYam Premium Member

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    Right at the three connections for the cluster? Not just the grounds in the bucket.
     
  17. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

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    Correct, putting the probe on the pin for the black wires in the connectors.
     
  18. jayrodoh

    jayrodoh YimYam Premium Member

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    Tough one man, if the grounds are good for all three connectors I can't really see how you would have 12V+ issues on all three harnesses as well. The lighting circuit is really simple, 12 volts into the connectors and the wires go right to bulb holders. Did you try and tow a truck with the wiring harnesses for the cluster?

    I would get my meter out again and check for 12V (positive and ground) on the harness (from bike) pins and see if you're getting power for the lighting, tach, and high beam individually.
     
  19. Dan Gardner

    Dan Gardner Well-Known Member Premium Member

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    Ya, I guess I'm just going to have to get in there and get a "running" voltage on each set of pins and see what we have.

    Does anybody know what the readings on the tach wires (orange and brown) should look like? Does that voltage vary with RPM?

    And now, just for a double kick in the @$$, I'm in quarantine with the covids. So it may be a few days before I can get out and do some more testing.
     
  20. XJ550H

    XJ550H Well-Known Member Premium Member

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    there is one wire running from 1 ignition coil to the tach tack counts the pulses of that wire and converts to rpm
    orange and brown wires will have 12 volts as the tci fires only 1 of these wires is connected to the tach.
     

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