Turn Signal Switch issue

Discussion in 'Troubleshooting & Diagnosis' started by Steve's 74, Mar 25, 2021.

  1. Steve's 74

    Steve's 74 Veteran Member Lifetime Gold Member

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    Need some help diagnosing this...
    My drivers side front signal does not work (most times) when I click it down. It does work when I use the lane change feature. Occasionally, after using the lane change feature, it will work until I turn it off. Next time, no worky. I've been able to reproduce this scenario many times.
    The rear always works. And I can hear the flasher clicking.

    Are there separate contacts for the front and rear?
    That might explain it, and I'll have to pull it apart, try cleaning the contacts, check for a lose wire, or replace the switch (if I can find one).

    FWIW, I tried spraying some electrical contact cleaner in there but no success.
     
  2. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    Yes, there are separate circuit for the front and rear on the "harmonica" plug to the steering column.
    I'm not positive if they are separate contacts at the turn signal switch.

    Do the hazard lights work properly?
    They use a different flasher but they use the same wiring for the lamps in the front of the car.

    My guess... It's the turn signal switch.
     
  3. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    From this pic, it looks like all of the wires at the "harmonica" connector lead back to the turn signal switch.
    Front and rear are definitely different circuits coming from the switch.

    upload_2021-3-25_13-22-25.png

    Probably a worn or dirty connection at the switch.
    It's no fun having to fish that connector through the column but that's what you will need to do if it needs to be replaced.

    You can pull the steering wheel and check it over closely before you take that step but it probably needs replacing. :(
     
  4. Jim Streib

    Jim Streib https://www.flickr.com/photos/[email protected]/albums

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    Yes there are different contacts at the switch for the right front turn signal, the left front turn signal, the right rear turn signal/brake, and left rear turn signal/brake.

    I have a feeling it is the switch in the column and possibly maybe corrosion on things ?. Maybe try working the switch a bunch of times to see if things clear up and start working as they should.

    It took me a while to figure out how the switch worked and I finally put together some drawings that might help explain things.

    https://www.flickr.com/photos/[email protected]/albums/72157648553149133

    Also to not shown in my drawing is that the front left and right turn signal wires are split to where one part goes to the front end light while the other branch on the wire goes to the instrument panel indicator light.

    Jim
     
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  5. Vettenick

    Vettenick Vettenick

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    Why don't you try to clean the socket? Sometimes just removing and installing the bulb a few times will clean it up. If not, try another bulb. The filament could be loose or damaged.
     
  6. Jim Streib

    Jim Streib https://www.flickr.com/photos/[email protected]/albums

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    Vettenick brings up a good point so I'll ask, does the indash indicator light on that side also not light up ?.

    If just the one in the front end that does not light up but the one in the dash does (and hopefully there are no issues there with a burnt out bulb or some other issue), then I have to think the turn signal switch is fine.

    Jim
     
  7. Steve's 74

    Steve's 74 Veteran Member Lifetime Gold Member

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    Thanks guys.
    When the front light does not blink, the dash light does not blink.
    When the front light blinks, the dash light blinks.
    I'll bet that terminal on the switch has some corrosion.
    But why does it work correctly when I use the lane change feature? Is the contact area different on the cam?
     
  8. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    ^ Exactly.
    Different contact area than when it's fully engaged.

    I was just looking at the wiring diagram and realized the dash indicator and front signal are on a branched circuit. (Jim mentioned this.)
    The connection to the dash circuit is not in the switch harness, it's branched on the mating plug.

    If the dash indicator works but the exterior signal light doesn't... The problem is downstream, towards the signal lights.

    If they both stop working at the same time... It's a problem with the electrical connection at the plug or somewhere in the switch.
     
  9. Steve's 74

    Steve's 74 Veteran Member Lifetime Gold Member

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    Thanks Terry.
    And I just also checked them when applying the brake. No difference from my original post.
     
  10. Jim Streib

    Jim Streib https://www.flickr.com/photos/[email protected]/albums

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    I wonder how square the contact are to each other or is there some wiping action going on. On a relay, the contact arm has somewhat of a wiping connection to the other side when it is moved and maybe the same is happening on the turn signal switch. Maybe too, when you turn the switch fully on to where it locks maybe some tension gets lost and connections are not made. I'm just guessing here as I have yet to take a signal switch apart.

    From what you are saying that when both the indash and front light on that side either work or do not leads me to believe there is a turn signal switch issue.

    Jim
     

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