Turn signals stopped working - 1970 Scout 800A

Discussion in 'General IH Tech' started by rlireland, Aug 20, 2019.


  1. rlireland

    rlireland Content Team Staff Member Moderator

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    Here's the story... All lights (headlights, parking lights, markers, brakes) including the turn signals have been working properly for the last 10 years or so. Then one day last month, I started up the Scout to go to a club meeting and noticed that the turn signals didn't come on. Neither side nor the dash indicators. All the rest of the lights still work fine.
    So I've been trying to systematically trouble shoot the issue. First thing I checked was the inline fuses to the flasher and hazard flasher. Both are good. Next I replace the turn signal flasher. Still no turn signals. Next, I pulled the steering wheel to check the turn signal switch. No voltage to any of the switch contacts - but why? Then I pulled the dash off to see if there was anything obvious with the connectors or broken wires. Haven't found anything abnormal yet. I know lighting issues are often associated with poor grounds but the fact that all the other lights work fine seems to eliminate this as a possible cause.
    Really starting to piss me off! Anyone experienced anything like this before? Is there something specific I should check that I haven't already?
    Thanks for any suggestions.
    Roy
     
    Last edited: Aug 20, 2019
  2. Bussy

    Bussy High Wheeler

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    Bulbs and grounds at the light checked?
     
  3. rlireland

    rlireland Content Team Staff Member Moderator

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    Yes. All bulbs and grounds are good on both front and rear turn signal sockets.
     
  4. Scoutnap

    Scoutnap Farmall Cub

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    May seem stupid but do you have power at the fuse?
     
  5. rlireland

    rlireland Content Team Staff Member Moderator

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    Thanks! I did not check that. That will be on my list for tomorrow.
     
  6. Scoutnap

    Scoutnap Farmall Cub

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    No problem I understand the frustration of electrical problems, my bulk head connector on the 75 scout 2 has started to show it's age every so often
     
  7. rlireland

    rlireland Content Team Staff Member Moderator

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    So I confirmed there is voltage at the flasher fuse. After I put the fuse holder back together, LOW AND BEHOLD, the turn signals work again! I'm concluding that there was an open circuit situation in the fuse holder but it could have been a loose wire somewhere else in the harness behind the dash. I probably moved every wire as I was fishing out the fuse holder and removing/replacing the fuse to check for voltage.
    Don't you just hate it when a problem is solved but you don't have a definitive reason why!

    Roy
     
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  8. rlireland

    rlireland Content Team Staff Member Moderator

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    But wait! There's more!
    I had removed the aftermarket steering wheel so there would be more room to access the wiring behind the dash panel.
    I replaced the dash panel and rechecked to make sure the turn signals were still working. They were.
    Then, I went about the arduous task of remounting the aftermarket (Grant-style) steering wheel. It's tricky because the shaft cover, steering wheel and horn contact plate must all be lined up in order for the three shoulder bolts that hold those three pieces to thread into the splined hub. The center steering shaft nut must also be tightened down to keep the wheel from slipping around on the shaft. I finally got everything lined up and tightened down. Checked the turn signals again... NOT working! I have no idea why installing the steering wheel would have had any effect on the turn signals. The horn wire is not hooked up because I don't have the proper connector for the yellow wire in the steering column. Never had it hooked up before when the turn signals were working, so it's hard to believe this is the issue.
    Could tightening down the steering shaft nut somehow have caused the turn signals to quit working? That's the only thing I did since the last time they worked.
    At this point, I'm pretty fried! I'll just drive it without turn signals.
    :death:
    Roy
     
  9. Dana Strong

    Dana Strong Lives in an IH Dealership

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    Which Scout is this happening to? It doesn't have a hazard switch, does it? I don't think anything should be grounding through the center shaft, so moving it slightly shouldn't be able to change anything, but loosening the nut might be a good way to confirm that.
    I assume you do have the proper wiring diagram, right?
     
  10. rlireland

    rlireland Content Team Staff Member Moderator

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    1970 Scout 800A. It does have a hazard switch that was part of the replacement turn signal switch and harness I installed about 10 years ago. The hazards never did work but the turn signals have always worked fine.
    I have a wiring diagram and have been able to trace some of the turn signal circuits. Haven't found anything suspicious.
    I'm going to try loosening the shaft nut since that's the last thing that changed before the turn signals stopped working.
     
  11. rlireland

    rlireland Content Team Staff Member Moderator

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    Ok...
    I loosened the steering shaft nut but still no turn signals.
    I removed the steering wheel completely. No turn signals.
    I'm now thinking that the problem must be something mechanical like a loose connection, perhaps in the inline fuse holder.
    I'm going to pull the dash panel off again and check voltage to the fuse and go from there.
    Roy
     
  12. Dana Strong

    Dana Strong Lives in an IH Dealership

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    If you can reach underneath it and touch/wiggle the wires and connections, that may be a good first step in determining if the problem lies there. Have the signal lever in the On position and watch/listen for their working while doing this.
     
  13. rlireland

    rlireland Content Team Staff Member Moderator

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    This just keeps getting stranger...
    I checked for and found voltage at the flasher fuse. But I still don't have any turn signals.
    Could the new flasher have gone bad?
     
    Last edited: Aug 22, 2019
  14. rlireland

    rlireland Content Team Staff Member Moderator

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    That's pretty much what I've been doing. While wrestling the dash and headlight harnesses around to get to the flasher fuse and trying to trace the turn signal circuits, I'm pretty sure I have touched every wire and connector in the dash!
    I don't like to do that with the battery connected though.
     
    Last edited: Aug 22, 2019
  15. Robert Kenney

    Robert Kenney Binder Driver

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    In these situations where a hi resistance is suspected, while the circuit is not under load (signal switch off) you will see full or close to full system voltage at the various test points. Of course this depends on how resistive your circuit is.
    If you have not already, with the TS switch on, go back and verify that you still have voltage when measured between your various test point and ground.
     
  16. Dana Strong

    Dana Strong Lives in an IH Dealership

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    IIRC, and according to the wiring diagram, the combined hazard/turn switch is rather complicated, so probably more difficult to check all aspects of. But...to get the lights to blink using either the turn or hazard part, the flasher module is involved. The old ones just use a thermal bimetallic switch, and it can go bad; that flasher can be jumped, for testing purposes. I sorta recall that two flashers are used with this setup, but won't check the books to confirm.
     
  17. rlireland

    rlireland Content Team Staff Member Moderator

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    Yes. The 800's used a separate flasher for the turn signals and the hazards. I can hear/feel the t/s flasher switch opening and closing if I touch a test light probe to the black wire on the hazard switch. This indicates to me that the flasher is working.
     
  18. rlireland

    rlireland Content Team Staff Member Moderator

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    I checked for and found voltage at the flasher (circuit 118) with the TS switch on.
     
  19. rlireland

    rlireland Content Team Staff Member Moderator

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    I've been letting things sit for a week and hoping that the electrical gremlins have been exorcised. Didn't happen. Turn signals still don't work. I've check every connector in the t/s harness for good contact. Wiggling wires around with the t/s signal turned on didn't help. I only get full voltage at the t/s flasher connector (circuit 118). I don't get voltage at any of the t/s switch terminals that I can reach (red and white wires) even with the t/s switch activated. I do get voltage at the black wire to the hazard switch. I don't know where else to check for voltage or what the voltage should be.
    Roy
     
  20. Dana Strong

    Dana Strong Lives in an IH Dealership

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    Without looking at the circuitry diagram, about all I can say is that contacts in switches do wear out (although I doubt it happened here) and it's theoretically possible that dirt or congealed/oxidized grease is also insulating them. You might try spraying some WD-40, contact cleaner, Oil of Wintergreen or some other solvent that won't ruin the plastic into the switch and work the contacts multiple times, then test again to see if it helped. If you weren't sure about how all the wires connected, sometimes drawing a simple diagram or two can help, but that seems not the case here.
    Where in the circuit are the flashers; before, or after the switches? If you bypass the blinkers, does anything change?
     

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