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Horn blows only when the car is running

494 Views 39 Replies 7 Participants Last post by  Pops @ Tri-5.com, 
T
Since I took out the ballast resisters the horn only works when the car is running. The horns worked before with the car off. There was a green, brown and white wire going to the pos side of the resistor I connected them to the pos side of the coil. I have tried every combination of wire hook up but cannot get the horns to work until the car is running. The horn relay has a constant 12v Any suggestions? Thanks in advance.
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vich57
The black wire at the horn relay should go directly to the two horns. Applying 12v to the black wire at the relay should be the same as applying 12v to both horns -- if they are wired correctly.

If there's 12v at the red horn relay wire, grounding the horn relay terminal with the green wire should cause the relay to trigger and activate the horns
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angs1957
vich57 said:
The black wire at the horn relay should go directly to the two horns. Applying 12v to the black wire at the relay should be the same as applying 12v to both horns -- if they are wired correctly.

If there's 12v at the red horn relay wire, grounding the horn relay terminal with the green wire should cause the relay to trigger and activate the horns
Click to expand...
What vich57 said is true but I suspect that you may not have the grounding wire working.

Go back to your horn relay (picture you posted), you have three wire`s, red, green and black.
Firstly unplug the relay, with a multimeter set on +12V, with ign key off, check from red wire to ground, meter should read +12V. If that good continue step below.
Next change the meter setting to continuity or "beep", check between black wire to horn (disconnect both horn wires), you should get a beep or continuity. If that`s good next step below.
Next from green wire to one side of meter whilst the other lead of the meter is grounded, press the horn ring you should get a beep or continuity, if you don't you`ll need to check from green wire at the horn relay working backwards to a plug at the base of your steering column, if that's good then you can check upstream from the base connector upwards to the horn ring by pressing it down without removing the steering wheel, if no beep remove the steering wheel and check there.
Hope it makes sense.
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Pops @ Tri-5.com
vich57 said:
The black wire at the horn relay should go directly to the two horns. Applying 12v to the black wire at the relay should be the same as applying 12v to both horns -- if they are wired correctly.
If there's 12v at the red horn relay wire, grounding the horn relay terminal with the green wire should cause the relay to trigger and activate the horns
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Agree...However, there are lots of "shoulds and ifs" there...Obviously this car has been messed with and not wired correctly.

Now try disconnecting the black wire on the horn relay and with your jumper wire connect +12V from the battery to it.
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T
Ok all the tests checked out ok I ran a wire from the batt to the black wire and it beeps.
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Pops @ Tri-5.com
Tbuff23 said:
Ok all the tests checked out ok I ran a wire from the batt to the black wire and it beeps.
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SUPER! Now disconnect the red and black wires on the relay and jumper them together
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T
I used some alligator clips and a test light to jumper the red and black wires together the light lights up but the horns do not beep.
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Pops @ Tri-5.com
Tbuff23 said:
I used some alligator clips and a test light to jumper the red and black wires together the light lights up but the horns do not beep.
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I would do it this way to eliminate anything funny going on inside the relay

Pops @ Tri-5.com said:
Disconnect the red and black wires on the relay and jumper them together
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T
Just bypass the relay?
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Pops @ Tri-5.com
Tbuff23 said:
Just bypass the relay?
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YES...And I would not be using a test light for troubleshooting this problem...Get a multimeter, even if it is an inexpensive one from Advance Auto: Advance Auto Parts: Car, Engine, Batteries, Brakes, Replacement, Performance & Accessories
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T
I have a good meter thank you for your patents and all the advice it is greatly appreciated. I will give this a try
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Pops @ Tri-5.com
Tbuff23 said:
I have a good meter thank you for your patents and all the advice it is greatly appreciated. I will give this a try
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Okay, thanks for hanging in there with me...I know some of these tests may seem redundant or unnecessary.
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T
2
Pops I have a question for you, looking at the wire diagram you sent the voltage regulator shows a blue and brown wire to the back of the gen. I have a blue and white to the back of the alt there was a brown wire to the ballast resister which now goes to the + side of the coil from the voltage reg. Post #3 and is jumped to post #4. My question can I do away with the brown wires? The white wire on the + side of the coil goes to the ign and the green wire goes to the starter. Thanks

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Pops @ Tri-5.com
Do you have an internally or externally regulated alternator?
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T
There is an external vr
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Pops @ Tri-5.com
Tbuff23 said:
There is an external vr
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Yes...But is is being used or just along for the ride

Does it liik like the stock original or something a little more modern?
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T
It looks modern it was hooked up to the + side of the ballast resister I put it to the + side of the coil I traced it back to the vr and I see it is on post 3 and jumpers to post 4.pic #1
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Pops @ Tri-5.com
Check out the attached articles...They show how the wiring should be set-up with an externally regulated alternator

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Shadetree55
If this isn’t an originality problem seems to me the simplest solution is grab a 3 terminal bolt on horn relay from NAPA and feed it off the battery terminal at alternator or from fuse box terminal that’s constant 12 volts. 1 wire to the horns and make sure the green wire from steering column is a completed circuit to the relay.
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T
Tbuff23 said:
Since I took out the ballast resisters the horn only works when the car is running. The horns worked before with the car off. There was a green, brown and white wire going to the pos side of the resistor I connected them to the pos side of the coil. I have tried every combination of wire hook up but cannot get the horns to work until the car is running. The horn relay has a constant 12v Any suggestions? Thanks in advance.
Click to expand...
Horn issue is now fixed there is an after market amp meter in the car it was fried I put a volt meter in place of it there is a red and black wire on the back of the meter I was thinking the black wire is a - but it is hooked to the pos side of the batt I jumped the wires together and the horn is now working with the car off.
Thanks For all the help
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Pops @ Tri-5.com
Tbuff23 said:
Horn issue is now fixed there is an after market amp meter in the car it was fried I put a volt meter in place of it there is a red and black wire on the back of the meter I was thinking the black wire is a - but it is hooked to the pos side of the batt I jumped the wires together and the horn is now working with the car off.
Thanks For all the help
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Glad you got it fixed and back to working as normal

Appreciate you getting back to us and letting us know what you found
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