Relay wiring question

Discussion in 'Technical' started by HarleyGA, Aug 11, 2017.

  1. HarleyGA

    HarleyGA Member

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    I wired my grill lights according to the attached diagram but can't get the lights to come on. Is this diagram correct?
    I'm not using existing wiring. Everything is brand new. The switch wire runs from the accessory terminal on the fuse box through a 20 amp rated switch and then out to relay connector post 86 and have voltage there. There is also voltage from post 30 to the positive post on the battery. The lights will work if I bypass the relay and go straight to the battery. I have five new 14 volt 30/40A relays that all test good. Ideas? relaywire.jpg
     
  2. Krazy Comet

    Krazy Comet Tom

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    If you have power at 30 & 86 then either terminal 85 has a defective ground or relay is defective...

    I'd be looking at the ground...
     
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  3. mavdog71

    mavdog71 Member

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    Harley
    As per your diagram you have wired right ... Do you have the right switch ??? Your going to need a 3 poll switch center terminal to #86 on relay one terminal to ground other to 12 volt power .


    __ ground
    __ __ # 86
    __ 12 volt power
     
  4. HarleyGA

    HarleyGA Member

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    Terminal 85 wire runs straight to negative post on the battery. I bought a package of five relays and sockets. All tested good. They all click when battery voltage is applied. The other two post pass the ohmmeter test. Zero ohms when power applied and plenty of resistance when voltage is removed. Really weird problem but I'll keep playing with it. Thanx.
     
  5. HarleyGA

    HarleyGA Member

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    I have a three post 20 amp lighted switch. I have 12 volts at the relay connector that goes to zero when the relay is plugged in. I have tried five brand new relays that all test good. Thanx for taking time to help me out.
     
  6. bmcdaniel

    bmcdaniel Senile Member Supporting Member

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    Did the grill lights work previously?
     
  7. HarleyGA

    HarleyGA Member

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    The car is a 73 so the grill lights once served as parking/turn signals. They work fine if I send battery power directly to them.
     
  8. Krazy Comet

    Krazy Comet Tom

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    Should be working, maybe you been watching too much Twilight Zone??
     
  9. HarleyGA

    HarleyGA Member

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    Actually I feel like I'm in a real life episode.
     
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  10. Grabber-1

    Grabber-1 Member

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    Test light on 86 .....clamp to ground....turn on switch test light comes on?
    no? No power coming from switch to relay check wiring and switch
    Yes clamp test light to 85 and repeat.(with wiring attached)
    Test light on?
    No. Bad connection in ground(spade or wiring)
    Yes. Pierce wire to sport lamps turn on switch. Test light lights?
    No. Bad spade terminal connection on relay or bad relay
    Yes . connect test lamp at sport lamps.turn switch on test light lights?
    No.wire to sport lamps bad.
    Yes. Check ground at sport lamps.
     
  11. yellow75

    yellow75 MaverickMike Supporting Member

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    How can something so simple be such a pia, you turn the relay on and it sends power to the light, 2 grounds and 2 power wires one fuse and a switch
     
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  12. mercgt73

    mercgt73 Member

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    1) Does the relay click when you flip the switch?

    2) Jump 30 to 87, do the lights work?
     
  13. HarleyGA

    HarleyGA Member

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    I walked away from this for a few days. Had a vacation planned anyway. Here is where I stand. The relay clicks when the battery is connected between 85 and 86 and zero ohms between 30 and 87 BUT no voltage between 30 and 87. Strange!Disconnect the battery from 85 and 86 and I get infinite resistance at 30 and 87. I bought these cheap relays in a five pack from Amazon. I can only assume that all five of them are bad. I'm going to buy a better quality relay and give it a go.
     
  14. yellow75

    yellow75 MaverickMike Supporting Member

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    Sounds like the relays are configured to be closed contacts when no power is applied which would mean the lights should be on when switch is in the off position with power hooked up to 30

    You could always just hook the lights to the switch if it has a high amperage rating and is fused until you get a different relay
     
  15. Krazy Comet

    Krazy Comet Tom

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    Going from memory, terminal 30 is power in for circuit to be controlled, 87 is power out to device(assuming relay is closed)... On five lug versions with 87A terminal, that should have constant power till the relay is triggered, then becomes a open circuit...
     

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