Brake light hookup

Discussion in 'Sparky's corner' started by LouV, Jul 26, 2017.

  1. LouV

    LouV Silver Level contributor

    I replaced the engine wiring harness in my '72 and cleaned up the dash wiring too. I have 2 small problems left I need a bit of help with.

    1. The brake light doesn't work when I turn the key on. I don't know if it ever did but I would like it to work.

    2. There is a Wire lug under a nut on the reinforcing frame under the dash by the fuse box. There is also a tab that has a wire attached to it. However, the big lug has evidence of a wire attached to the ground lug. Any idea of what was grounded to that lug?

    Thanks,

    Lou
     
  2. CJay

    CJay Supercar owner Staff Member

    Let me ask a stupid question on the brake light bulb , is the bulb capable of lighting up?

    A picture might help on the fuse box issue.
     
  3. LouV

    LouV Silver Level contributor

    The light works, I swapped the brake and gen light and both bulbs were good. I'll get a picture up tomorrow.

    Thanks,

    Lou
     
  4. CJay

    CJay Supercar owner Staff Member

    If the bulb is good, you missing the positive or the ground. If you take the tan wire off the brake combination valve or the tan wire off the E brake assy and ground it with the ignition in the ON position, the light should come on because your giving the bulb its ground.

    So you need to verify that you have a good connection at the back of the gauge at the tan wire. I would check for continuity with ground at that wire- Ground the tan wire going to the combination valve and then check for ground at the back of the gauge with a test light or a DVOM. If that wire has a good ground at the back of the gauge, then your missing the power leg at the gauge which is the pink wire. But of you were missing the power, the other warning lights wouldn't work.
     
    Last edited: Jul 26, 2017
  5. LouV

    LouV Silver Level contributor

    Thanks for the help. The light works with a ground on either brake switch but it does not come on when the key is turned to on. As far as I know, it should come on when the key is in the on position as a bulb test.

    2. There is a Wire lug under a nut on the reinforcing frame under the dash by the fuse box. There is also a tab that has a wire attached to it. However, the big lug has evidence of a wire attached to the ground lug. Any idea of what was grounded to that lug? Here is a picture of the grounding lug. It is sticking out by the 2 pink wires. It has a ring connector wire an old wire attached but broken off and a tab connector with a black wire attached. I can't seem to find anything that would go there, either a wire with no end or a wire with a ring terminal.

    IMG_4384.jpg

    Lou
     
  6. CJay

    CJay Supercar owner Staff Member

    Hard to see, but any factory ground wouldn't be a ring terminal. It would be a brass terminal with a male spade connector. As an example, there should be one attached to the wiper switch mounting screw
     
  7. LouV

    LouV Silver Level contributor

    Thanks, I don't know that this was a factory ring terminal. Since there is also a spade terminal on the screw I will assume that this was the factory ground and the ring terminal was added by someone at a later date.

    Lou
     
  8. CJay

    CJay Supercar owner Staff Member

    A better pic might help.
     
  9. LouV

    LouV Silver Level contributor

    This is the best I could do.

    IMG_4391.jpg
     
  10. CJay

    CJay Supercar owner Staff Member

    I cant really tell. Im sure if you take it out, you can probably tell if its factory or from an auto parts store.
     

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