Horn wiring question

[AngryPirate]

So, I've replace the steering wheel guts for the horn (correctly I assume) and then I'm trying to test the green wire coming out of the other side.

I was assuming that pressing the horn button creates a ground, so with my tester ground-side attached to the green wire and the + side touching some power. So I would expect when I press the horn button the tester light should light up. It doesn't.

Next question, does anyone have a picture of how the horn relay is wired? I looked at the wiring diagrams and I don't think I can glean from those which wire goes where on the prongs of the relay.

So, is my assumption on the horn button being the grounding part of the circuit correct?

Just a note, I'm no longer using a voltage regulator external module either; just a alternator with an internal regulator.

Thanks for any help!

- Scott

[tincan1966]

On a typical 3 wire horn relay- you will have 12V+(battery) power in-normally a red wire. The green will be "hot" 12v+ out to horn when horn button depressed, or the black wire is grounded(which is the wire going up thru column)

Make sure you have good connection thru the column wire harness plug.
Do you have 12V+ at the relay?

[AngryPirate]

Originally Posted by tincan1966

On a typical 3 wire horn relay- you will have 12V+(battery) power in-normally a red wire. The green will be "hot" 12v+ out to horn when horn button depressed, or the black wire is grounded(which is the wire going up thru column)

Make sure you have good connection thru the column wire harness plug.
Do you have 12V+ at the relay?

thanks tincan!

I believe I do have the 12V+ relay. I'll double check though.

[AngryPirate]

so, I guess I could just run through the combinations of the 3 different wires, but does anyone know which prong is which?

Thanks!

[luvbowties]

Hey, look here, esp. at #2 along with #3.
sam

>> http://67-72chevytrucks.com/vboard/s...d.php?t=453978 <<

[luvbowties]

Originally Posted by AngryPirate

so, I guess I could just run through the combinations of the 3 different wires, but does anyone know which prong is which?

Thanks!

My thinking is the lonely one is the one that goes to horn ring to furnish/complete a ground for the relay coil; this then causes the 2 side-by-side ones to make contact. The 2 side-by-sides: one goes to 12-volts while its mate goes to horn terminal--should not matter which goes where.

See picture of a 3-prong relay below. It came from an "I don't recall" site on the 'net. *Really, the 'free' end terminal from the relay coil should make constant contact to the 12-volt source: then when horn is depressed & other end of relay coil is grounded (by horn ring), current flows thru relay coil to magnetize it.

I'd test the terminals & this educated-guesswork with a meter or light before installing and "smoke-testing" it on the vehicle. My $ is on the above reasoning being correct, though!
HTH,
sam

[AngryPirate]

Originally Posted by luvbowties

My thinking is the lonely one is the one that goes to horn ring to furnish/complete a ground for the relay coil; this then causes the 2 side-by-side ones to make contact. The 2 side-by-sides: one goes to 12-volts while its mate goes to horn terminal--should not matter which goes where.

See picture of a 3-prong relay below. It came from an "I don't recall" site on the 'net. *Really, the 'free' end terminal from the relay coil should make constant contact to the 12-volt source: then when horn is depressed & other end of relay coil is grounded (by horn ring), current flows thru relay coil to magnetize it.

I'd test the terminals & this educated-guesswork with a meter or light before installing and "smoke-testing" it on the vehicle. My $ is on the above reasoning being correct, though!
HTH,
sam

Sweet Sam!

I thought something similar, i was going to use a continuity tester on the 2 side-by-side prongs, but I wasn't sure what to do with the 3rd (presumed ground) prong. I guess just ground it to something? anything?

I'll give it a shot!

Thanks!

- Scott

[AngryPirate]

Okay, so I figured it out, finally.

So, using the standard 3 prong relay you would get from any parts store for these years, this is what I came up with (that works). See the first picture.

The truck manual lead me astray as to the location of the ground wire (steering column horn button wire). I included those pictures as well. This did not work for me.

I also included the horn relay, sans cover so you can see the insides.

Picture 1 - This worked (red - to battery, green - to horn, empty prong - will be connected to the horn button wire).

Pictures 2 & 3 - from the truck manual. prong orientation incorrect for current, readily available horn relays

Pictures 4 & 5 - insides of horn relay