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Disconnect of Horn Relay

Discussion in 'The Hokey Ass Message Board' started by 64impala, Oct 31, 2012.

  1. 64impala
    Joined: Sep 14, 2012
    Posts: 79

    64impala
    Member

    If I disconnect the entire "horn relay" unit/wire(s)/harness (including the "Bat" wire from the relay to the battery) will it prevent the ignition switch from starting the engine? Or is the "horn relay" completely independent? :confused:


    Make: Chevrolet
    Year: 1964
    Engine: Smallblock
     
  2. manyolcars
    Joined: Mar 30, 2001
    Posts: 8,792

    manyolcars

  3. oj
    Joined: Jul 27, 2008
    Posts: 6,343

    oj
    Member

    Are there a pair of #10wires a Red and one other? if Yes, then join those two and see if things don't start to act right. Some GM years use the horn relay to feed things as i recall the #10 running across the top of the radiator going to the relay and then on into the car with the headlight etc wire harness.
     
  4. 64impala
    Joined: Sep 14, 2012
    Posts: 79

    64impala
    Member

    The wire configuration off of the main harness:

    1. 10g red wire from relay "bat" connection to car battery.
    2. 14g and 16g red wires from main harness to second horn relay connection.
    3. 16g red and green wires connector to horn relay connection.
     

  5. 24riverview
    Joined: Jan 13, 2008
    Posts: 1,008

    24riverview
    Member

    In 64 the horn relay was used as a termination point for some of the "hot" wires in the system, feed from battery, alternator battery, regulator feed, ignition switch, etc. If you need to remove the relay you'll have to tie all the red wires together as oj said. Having an issue or just trying to clean it up under the hood?
     
  6. Mr48chev
    Joined: Dec 28, 2007
    Posts: 32,163

    Mr48chev
    ALLIANCE MEMBER

    Here is a link to what should be the wiring diagram for that car.
    http://www.tocmp.com/tOCMP/wiring/5765wiring diagrams/Chevrolet/MWireChev64_3WD-075.jpg

    Back half of the car here.
    http://www.tocmp.com/tOCMP/wiring/5765wiring diagrams/Chevrolet/MWireChev64_3WD-074.jpg

    If you click on the diagram after you open it it should expand and be easier to read.

    The red wire that ties into the black wire from the battery to the horn relay feeds the ign switch, headlight switch and lighter and probably the fuse block.
     
    Last edited: Oct 31, 2012
  7. 64impala
    Joined: Sep 14, 2012
    Posts: 79

    64impala
    Member

    OJ and 24riverview: I think you guys are on the right track, when I disconnected the horn relay completely, my ign switch had no power.

    My problem started with a possible bad ground issue. Blowing 10amp fuse on the "IGN" fusebox slot when placing the ignition switch into the "On" position.
    So I figure it is either a bad ignition switch, bad ground, or horn relay connection!?
    Assuming my horn relay is tied into the ignition power configuration, and my horn relay was bad, would that cause my ignition switch to not receive power??
     
  8. The horn relay is also used as a junction box in 64 so even if it failed internally you should still get power to the ignition switch through the buss bar that is part of the relay. This is shown on the diagram.
     
  9. 24riverview
    Joined: Jan 13, 2008
    Posts: 1,008

    24riverview
    Member

    Fusebox look like this?
    [​IMG]
    Which fuse is blowing? The terminals marked ignition on the left side are for adding accessories that you want to go on and off with the key.
    They are tied into the back up light or wiper fuse. If one of those is blowing you need to look at those circuits or whatever may be plugged into the terminals on the left. There is no fuse protecting the ignition switch. If you had that big a problem at the horn relay you'd be seeing
    some pretty big sparks when hooking the red wires to it. Again this is with the factory harness if it's somebody else's we'd need to know which one.
     
  10. 64impala
    Joined: Sep 14, 2012
    Posts: 79

    64impala
    Member

    I have an old Mallory HEI setup, here's how it's setup on the "Fused IGN" slots and I'm using a factory harness setup.

    Top Left fusebox "fused ign": hot wire going back to the positive side of ballast.
    Note:
    The old (10yrs) Mallory HEI configurations had a ballast, I know most new HEI systems don't include it, but I've been running that way since I purchased the car 8 years ago!

    Top Left fusebox second slot for "fused ign": positive wire going back to the Edelbrock 600 Performer autochoke + slot.

    What should/can be used on the "Bat" fusebox slot?
     
  11. 64impala
    Joined: Sep 14, 2012
    Posts: 79

    64impala
    Member

    Update:

    I have reconnected the stock "horn relay" configuration for the purpose of trouble shooting the original problem of the fuse blowing on the "IGN" fusebox 1st upper left slot when turning the ignition switch to the "On" position.
    I will go through a number of tests on the culprit fusebox slot using a 10 amp relay so that I don't keep blowing fuses and report back!

    Note: Now that the stock horn relay config is reconnected, I now have 12v power at
    the fusebox.
     
    Last edited: Nov 2, 2012
  12. 64impala
    Joined: Sep 14, 2012
    Posts: 79

    64impala
    Member

    TEST RESULTS:

    Using a 10 amp circuit breaker, I performed the following test(s) on the IGN #1 and #2 slots at the fusebox.

    1. Removed all wires from both #1 & #2 ign slots: Result: circuit breaker tripped.
    2. Connected "ballast +" wire to slot #1: Result: cb tripped.
    3. Connected "ballast +" wire to slot #2, #1 slot empty. Result: cb tripped.
    4. Connected "auto choke +" wire to slot #1, slot 2 empty. Result: cb tripped.
    5. Connected "auto choke +" wire to slot #2, slot 1 empty. Result: cb tripped.
    6. Un-mounted ignition switch, left it hanging away from dash & left connected, moved wires ignition wiring hardness wires around, connected ballast +" wire to slot #1. Result: positive test.
    7. Connected both ballast+ and auto choke+ wire to slots #1 & #2 respectively, replaced 10 amp circuit breaker with 10 amp fuse, cranked engine over successfully.

    Question: I suspect I have a faulty ign switch (which is relatively new), a bad ground in the switch or switch wires.
    Where do I go from here as far as additional tests?
     
  13. If the fuse now longer blows when the switch is removed from the dash it sounds like the ignition switch has an internal short to the case. If you remount the switch does the circuit breaker trip with everything connected to the switch? I also see a ground terminal with a green wire going to it in the wiring diagram. If that is hooked to the wrong terminal on the switch I believe that it could cause the fuse to blow.If you see a green wire try disconnecting only that one and see what happens.
     
  14. 64impala
    Joined: Sep 14, 2012
    Posts: 79

    64impala
    Member

    Insured there were no loose wires from main harness into switch, inspected switch wires for exposure, re-grounded switch, and reinstalled switch to dash.
    Tested the switch several times, engine cranks and starts with no further issues!
    I will continue to monitor and replace ign switch if the issue resurfaces!
    Thanks for everyone's help!
     

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