Low beams are not working!

Electrical and Ignition

  1. MrJLR

    MrJLR Built, not bought FABO Gold Member

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    My high-beams AND low-beams would work and switch back and forth with the floor mounted switch before I installed my headlight relay kit from crackedback.

    But now I only have high-beams...if I step on the switch - the lights go off (low-beams "should" have come on).

    Crackedback has been awesome and more than helpful and we checked his parts by jumping off the battery with a wire - his relays and harness all work perfect. I can get both high and low beams by jumping it.

    He thinks I have a ground issue somewhere in my original system. Sounds reasonable to me.

    I've looked and looked and can't seem to find it! ARG!!!!!

    Any ideas or suggestions?

    Thanks in advance!

    :coffee2:
     
  2. memike

    memike Super Moderator Staff Member FABO Gold Member

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    Sounds like the switch it self to me if you can jumping at the switch, I have seen new switches that was bad ..
     
  3. MrJLR

    MrJLR Built, not bought FABO Gold Member

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    Hmmm.....that's possible.
    I forgot to mention I replaced the switch too with no results :banghead:

    I can try bypassing the switch.....but BOTH the old and brand new switch have not worked.....
     
  4. mopardude62

    mopardude62 FABO Gold Member FABO Gold Member

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    Yea, I agree Crackedback is a GREAT guy!! Have you tried swapping the relays to see if maybe you have a bad relay?
     
  5. MrJLR

    MrJLR Built, not bought FABO Gold Member

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    Yes.....I swapped the relays - no dice....
    Checked the fuses....both are good.
    Plus, we jumped from the battery to his system and both high and low beams worked.....

    Part of the fun with these cars - right?!!!!!
     
  6. mopardude62

    mopardude62 FABO Gold Member FABO Gold Member

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    You know if he thinks it might be a ground issue with your original wiring, can you unplug the wires from Crackedback's relay harness from your headlights and plug your original wiring back into the headlights and see if you have low beams? If you do have a ground issue in the original system, this will show it pretty quickly.
     
  7. MrJLR

    MrJLR Built, not bought FABO Gold Member

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    I've considered that.....it's a lot of work but I may end up doing that.
    I'm just hoping I find a loose/hanging ground somewhere.....wish I understood more about the circuit. I'm not too hip on electrical...!
     
  8. 67Dart273

    67Dart273 Well-Known Member

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    All you have to do is logically think this through and find it. You can't just easter egg it.

    Get your meter out and probe relay power to the low beam relay.

    1....It should be getting power to the coil when low beam is selected. If not backtrack to the bulkhead connector and probe it there. If not there, then backtrack to the dimmer switch and verify it at the wire coming out of the dimmer connector.

    2....Make sure the relay socket coil wire is grounded. Easy. Probe the socket, and ground. Should be close to zero resistance

    3...Verify power is coming INTO the relay contact

    Since I don't know how these relays are wired, this is only a guess

    Hot fused headlight power should be on all the time to 30

    coil connection 85 should be ground

    coil connection 86 should be hot with low beams selected

    [​IMG]

    If all the above checks good, select low beams and go out and unplug a headlight. You have power there? If not backtrack back to the relay. Should have power to 87 with low beams selected.
     
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    • MrJLR

      MrJLR Built, not bought FABO Gold Member

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      Thank you! I'll try all that tonight after work.....
      At least now I have some new direction to look!

      :coffee2:
       
    • MrJLR

      MrJLR Built, not bought FABO Gold Member

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      Is there only one fuse (originally) for both the high-beams and the low-beams?
       
    • 67Dart273

      67Dart273 Well-Known Member

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      Yes.

      Power for ONLY the headlights comes from the ammeter harness directly TO the headlight switch. With switch on, power goes down TO the dimmer switch. This is a simple 3 terminal SPDT switch, that is, two terminals are always connected, and when you mash the switch, the power and the "was dead" terminal is now connected

      One out for hi, and this branches off to feed the high beam indicator

      One out for lo

      both these wires then go through the bulkhead, out and around to the headlights
       
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      • MrJLR

        MrJLR Built, not bought FABO Gold Member

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        Awesome....I'm understanding it better now!
        Can't wait to get out of work and check it out!

        Thanks a bunch!
         
      • crackedback

        crackedback FABO Gold Member FABO Gold Member

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        Have you probed the factory headlight plug with a voltmeter?

        Violet hot on low, red on high and there should be no bleed over to either.

        I assumed your original set up worked properly. If there is no power to the violet wire, check/probe the bulkhead connector.
         
      • MrJLR

        MrJLR Built, not bought FABO Gold Member

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        I will check that too...!
         
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