1973 horn info, ok i'm confused.. Options

[buhs914]

So i bought a new low tone horn because the previous horn sounded like a miniature train. I thought it would be a direct swap until i found that it had these

they were powered by an air pump in the spare tire area that was wired to a relay right next to it.. WTF? i looked at the wiring diagram to see what wires actually go to the stock horn and i couldn't find those wires in my car.. i also find the wiring for the fog lights that i don't have (idk if those are supposed to be there or not)..

could someone please post a picture of the stock horn with the wiring and relay. i need a reference.

[EdwardBlume]

Those are air horns vs electric horns... its likely the original electric leads off the harness which also connect to the fog lights, are still there...

Take the bumper off and look at the harness that runs in front of the spare to see what the PO hacked...

[Mike Bellis]

I bet the wires to the new relay are the wires to the old horn. The factory relay is above the fuse panel. I would bet it's still there.

[Jeffs9146]

The air pump would need to build pressure in order to function. So I would guess that the pump should be activated when the key is turned on. It would then build enough pressure and shut off. When the horn is pressed the ground from the original horn loop is completed and activates a relay near the pump that releases the compressed air to the horns! (IMG:style_emoticons/default/wacko.gif)

[Mike Bellis]

The air pump would need to build pressure in order to function. So I would guess that the pump should be activated when the key is turned on. It would then build enough pressure and shut off. When the horn is pressed the ground from the original horn loop is completed and activates a relay near the pump that releases the compressed air to the horns! (IMG:style_emoticons/default/wacko.gif)

Most of those pumps make instant pressure. Push horn button, 1/2 second later hear the horn. Pump only runs when button is pushed.

[Jeffs9146]

Most of those pumps make instant pressure. Push horn button, 1/2 second later hear the horn. Pump only runs when button is pushed.

Wow, 1/2 second could kill you! Mine had a small can that stored enought air for instant sound!

(IMG:style_emoticons/default/confused24.gif)

[buhs914]

Most of those pumps make instant pressure. Push horn button, 1/2 second later hear the horn. Pump only runs when button is pushed.

Wow, 1/2 second could kill you! Mine had a small can that stored enought air for instant sound!

(IMG:style_emoticons/default/confused24.gif)

yeah mine had a can as well.

so i will more than likely have to remove the bumper and inspect the wiring to find my missing wires and see what the DAPO screwed with?

[buhs914]

(IMG:style_emoticons/default/icon_bump.gif)
I'm still looking for some pics of the stock horn with the wiring if anyone has any.. the wiring diagrams are good but a visual aid would be even better

[jt914-6]

Hard to photograph, but on my '74 the fog light/horn wires come out on passenger's side in front trunk. The horn wire is black with yellow stripe for hot and brown for ground....hope this helps.....

[pcar916]

Most of those pumps make instant pressure. Push horn button, 1/2 second later hear the horn. Pump only runs when button is pushed.

(IMG:style_emoticons/default/confused24.gif)

My Fiamm horns blow LOUD as soon as I push the button... literally no delay that I can detect. I was surprised at that by the way. I expected a slight delay, but essentially there isn't one.

1/2 a second is maybe too long. But since most humans generally take 2 seconds to recognize and another little while to respond to a situation, my take is that one is usually better off driving around an issue rather than tootin' at somebody who may accelerate into the problem rather than act properly.

I kept my hoses short to minimize any potential delay. If there is a delay, I would always check for leaks first, then try a new pump. The old one may not spin up fast enough or have a bad diaphragm or impeller seal.

Good luck

[McMark]

No relay in the stock horns. The wiring comes from the loom which comes out from under the gas tank on the drivers side. The wires for the horn pop out of the loom as it runs along the front of the chassis, under the metal 'shelves'. Wire color is a black with a yellow stripe, and a brown one. The connectors on the drivers side should have double wires in the connector, since the DS horn 'feeds' power to the PS horn.

Hope that helps.

[buhs914]

No relay in the stock horns. The wiring comes from the loom which comes out from under the gas tank on the drivers side. The wires for the horn pop out of the loom as it runs along the front of the chassis, under the metal 'shelves'. Wire color is a black with a yellow stripe, and a brown one. The connectors on the drivers side should have double wires in the connector, since the DS horn 'feeds' power to the PS horn.

Hope that helps.

well the wiring diagram shows a relay that's connected to the black/yellow wire.. lol

when i hooked up the black/yellow wire and brown wire to the stock horn and tested it, all it did was make a clicking sound.. i also have two black/yellow wires near the horn area (IMG:style_emoticons/default/blink.gif) ... i swear the PO was drunk or just plain retarded when he did this setup..

[buhs914]

Hard to photograph, but on my '74 the fog light/horn wires come out on passenger's side in front trunk. The horn wire is black with yellow stripe for hot and brown for ground....hope this helps.....

thanks for the pic. that actually helped out alot

[jt914-6]

Hard to photograph, but on my '74 the fog light/horn wires come out on passenger's side in front trunk. The horn wire is black with yellow stripe for hot and brown for ground....hope this helps.....

As was said after my post....there should be horn wires on driver's & passenger's side....the pic was from the passenger's side. The other thick black loom in the pic is for a fog light.

[Triaddave]

with my wife's 74 car, the relay operates the horn and the wipers. the relay is on the fuse panel. is this right?

[McMark]

Figured you meant there was a relay added by the person who installed the horn.

[buhs914]

Figured you meant there was a relay added by the person who installed the horn.

oh ok lol yeah the PO added a relay for the air canister. haha

[McMark]

(IMG:style_emoticons/default/lol-2.gif)

[silver74insocal]

So i bought a new low tone horn because the previous horn sounded like a miniature train. I thought it would be a direct swap until i found that it had these

they were powered by an air pump in the spare tire area that was wired to a relay right next to it.. WTF? i looked at the wiring diagram to see what wires actually go to the stock horn and i couldn't find those wires in my car.. i also find the wiring for the fog lights that i don't have (idk if those are supposed to be there or not)..

could someone please post a picture of the stock horn with the wiring and relay. i need a reference.

dude i want to purchase your horns!!! please let me know if you want to get rid of them. i want to scare people with them ...a miniature train sound would be awesome

[Mike Bellis]

If the PO added a Bosch type relay, take the wires from terminals 85 & 86 off the relay and put them directly to your stock horn. If you heard the relay "click" then the circuit is good and should sound your stock horn directly. Air Horns like what the PO added need the extra relay factory horns do not.