Wire Chase question for 79 GT brake light / hazard flasher issue

Discussion in 'Ranchero Tech Help' started by Green79, Jul 13, 2019 at 7:40 PM.

  1. Green79

    Green79 In First Gear

    Messages:
    4
    Hello, my 'Chero project has been going along fairly well.. It has received so far a carb rebuild, a new rag joint, a new radiator, had the trans pan dropped and new filter & fluid put in and a new vacuum modulator put on (trans still doesn't shift up from 1st to second, but that isn't the topic of this thread).. a junk yard tail gate handle put on, new tailgate straps made from some hardware store cable.. wiring fixes and bulbs.. and so on.. The issue I need to get addressed next, so I can put some careful miles on it to work the fuel through and see if the trans fixes itself is brake lights and hazards.

    Here is what I have so far.. the turn signals work.. front & rear.. and it has new flasher cans for both turn signals and hazards but I still get no brake lights and no hazards.. it looks like the brake light switch does work and I worked on the wiring from the switch to the rest of the harness. It sounds like this circuit goes up into the column and through the turn signal switch on these but I can't find a correct wiring schematic for what wires I need to chase. Anyone have one? Thanks fellas. (btw, the gauge cluster is out of it right now, I could possibly see the hazards needing the indicators in the dash to work right but would be surprised if brake lights did)
     
    andrewok1 likes this.
  2. andrewok1

    andrewok1 In Maximum Overdrive SILVER MEMBER GOLD MEMBER

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    Location:
    ocala ,florida
    the blinker or directional switch in the steering column same problem on my 1972 , replaced no more problems and 4 ways blink
    all the signal light circuits are in that switch
     
  3. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    Location:
    Everett, WA
    Yup, I also have a '79 GT, I rebuilt the column several years ago, and replaced the switch due to no turn signals. The switch couples the load onto the flasher to make it interrupt current flow. The flasher switch cam is where the contact is made, but if the contact buttons are too worn down (as mine were), then a new cam won't make contact. So pull the steering wheel, and on the left is a 1/4" hex screw...remove it, then carefully work the cam off. The contact wires are underneath the cam, and the contact buttons are in the switch body. The wires should be round with no flat spots, and the buttons should be 'domed.' If those buttons are worn off, no replacement cam will fix that.
     
  4. Green79

    Green79 In First Gear

    Messages:
    4
    Hey guys thanks for the responses. This rig had been parked for the last 20 years and they worked when it was used last. I think it's more likely that some mice got to the harness somewhere and a wire has been chewed. I would prefer to see a wiring diagram and chase the wires than assume it's the switch. Anybody have a full wiring schematic? Thanks.
     
  5. Doc76251

    Doc76251 In Fourth Gear

    Messages:
    340
    Location:
    Virginia Beach, VA
    The brake and the hazards are different circuits. Since you have the gauges out you could do a continuity check by tapping the correct pin on the gauge block and probing the light socket at the rear via a "tone and probe" type device, that would tell you if the wires are still connected which would lead you to answers at one end or the other.

    Cheers,

    Doc
     

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