Front Blinker Funkiness

Discussion in 'Sparky's corner' started by Marc, May 20, 2019.

  1. Marc

    Marc Active Member

    Very strange behavior with my front indicators that varies with use of headlights. Neither mode is correct.
    • Headlights off:
      • Driver's side indicators, front and marker, work as expected.
      • Passenger's front indicator works as expected, front marker does not.
    • Headlights on:
      • Driver's side front indicator works as expected, front marker does not. However, if I unplug 1157 bulb the marker light illuminates.
      • Passenger's side indicators, front and marker, work as expected.
    The marker bulbs are LEDs. I have not read any reports of LED marker bulbs causing issues. Any suggestions?
     
  2. TrunkMonkey

    TrunkMonkey Well-Known Member

    Check all the grounds first.
    (especially if it worked correctly and nothing was done to any wiring)
    The power to the lights will flow to ground through other light wiring and cause odd lighting as a result.
     
  3. Marc

    Marc Active Member

    I think you are correct. While the headlights are grounded at the core support, the grounds for the indicators and markers run through the harness into the firewall right about where the fuse panel is mounted. I did not see where the ground wires terminate. Where should I be looking? Thanks in advance.
     
  4. TrunkMonkey

    TrunkMonkey Well-Known Member

    Almost all lighting is ground pathed through the connectors to lamp housings, the frame/body panels and dash bezels to dash/cowling. (light switch/ignition switch)

    So, if you have a bad ground(s), the path then goes through least resistance via the wires/lights and that will cause other lights to illuminate (and usually dimmer) than as if they are powered correctly.

    A multi meter is your friend and a good schematic is your bestest friend.

    First thing I would do is pull each bulb, and see if the contacts are in good shape, that the springs that keep them pressed against the bulb are good and then where the bulb housings are grounding to the chassis.

    Then check to see that you have good battery ground to the engine, and that battery is grounded to the body/frame, and that the engine is also grounded to the body/frame. Then that the body is grounded to the frame.

    Then that the bumpers are grounded to the frame.

    Rust/corrosion/vibration and time can cause grounded components to fail or become weak and or intermittent.

    Try lights in order, say, only parking lights, or only brake lights, or only headlights and see what works correctly and what does not.

    You can "make" temp grounds using alligator clips and ground each bulb/device as you go, to see if it makes any changes. Make notes as you go along, and if you need help, post again.
     
  5. gstewart

    gstewart Well-Known Member

    U may have to unwrap the covering on the the wiring harness and follow the wires back to ground. Follow Trunkmonkey's advice.
     
  6. bostoncat68

    bostoncat68 Platinum Level Contributor

    I would buy some CRC contact cleaner and clean all the bulb sockets - a little brass brush is your friend. I have used a little brass brush on a Dremel tool to remove real rust and gunk. Then add a tiny drop of ox gard on the contacts. You can then use some dielectric on the rest of the socket. (The ox gard is conductive so don't smear it all over. The dielectric is non conductive so it's better to use ox gard on the contacts.) This may seem fussy but it is a great way to fix issues and prevent problems over time as you'll keep moisture out...
     
    TrunkMonkey likes this.

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