Turn signals occasionally do/don't work

Discussion in 'Troubleshooting & Diagnosis' started by MP81, Aug 21, 2019.

  1. MP81

    MP81 Veteran Member

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    Ahh, okay - so that does make sense, as they need to be available no matter the state of the key in the ignition (constant hot).

    And the single power wire coming from the fuse box "into" the column is the purple one. If I have power there (with ignition on), but no output at the four turn signal wires, then it is likely the switch or the harness. That all sound comprehended correctly?
     
  2. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    That's the way I read it.
    Hope it's a simple fix!
     
  3. MP81

    MP81 Veteran Member

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    Sweet, sounds like it shouldn't be too complicated to check pretty quickly on my own.

    And yes, I hope so too - I'm sick of having to work on this car. Granted, this doesn't affect driveability, but I'm one who nearly always uses my turn signals, so for them not to actually do anything, that bothers me.

    Thanks again for all the help - I'll post back up on what I figure out!
     
  4. grzewnicki

    grzewnicki Veteran Member Lifetime Gold Member

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    Best to try sorting it out when they don't work by checking power going in the connector on the bottom of the column. If they don't work with power available at the connector on the bottom of the column then it is inside the column. If you don't find power at that connector trace it back to the flasher and see if yo have power going into the flasher. The intermittent problem makes it a little hard to diagnose. When they work that is telling you grounds at front and back are good so I doubt it is a ground problem, definitely sound like a power issue. Imagine it could be the contact in the switch assembly since I believe one contact makes contact with either left or right side contact so maybe the problem lies with the contact providing power. I got a switch assembly in front of me but it is very hard to tell what is going on behind the moving parts
     
  5. MP81

    MP81 Veteran Member

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    So, this ended up being much less complex than we were all thinking, and I kind of feel like an idiot for not starting here...

    ...but let's go back a bit. I took the test light and determined that I was not getting any power at the purple wire at the column connector. So at that point, I remembered that I have the '81 service manual sitting in the garage, and it has an "electrical troubleshooting" section. I flipped to the turn signal bit and that's where I noticed that it asked if the backup lights were working or not...they were not! I had not noticed this before, since I wasn't looking for it - but they absolutely should have been on with the key on, since it is a manual. I also had no idea they were on the same fuse.

    Which brings me to where I should have started - the damn fuse. I had brought out that service manual initially to see where the turn signal fuse was, before discovering everything above. Took a look and saw...this:

    P1130309.JPG

    And guess what? Move the wires around and you could make the signals work or not work! Bingo.

    I'm not sure why a 20A breaker was wired into where a 20A fuse goes, but it seemed awfully janky. Replacing this with a 20A fuse, I may see why - even the fuse seems susceptible to picky placement. Both were seated in there pretty good, but if it moves just a little, suddenly it doesn't work anymore.
     

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