72 RR Horn

[Eric]

I would suggest everyone also mention at which plant their car was built and what the build date was. It's possible it varied by plant or was a mid year change....

[BlackGTS]

What I meant in saying that neither side of the Year One harnesses had a horn wire was my engine harness is for a 72 and goes to the right side of the car and since the horn is on the left side shouldn't have a horn wire and it doesn't.The forward light harness that goes to the left is for a 71 to accommodate my 71 parking lights and doesn't have the horn wire since a 71 horn is on the right side,I think.

On the 71 harness the wire coming out of the firewall block that should be for the horn is black and has a cup on the end.It looks like it should attach to the proportioning valve.I am thinking I can wire the horn off of that.

While we are talking about horns,is the little screw on the horn to adjust the tone?

[72Rdrnner]

All this horn talk got me to thinking. (I know that's dangerous) Since I have two nice and shiny, all painted & decaled, genuine Roadrunner horns, and two horn hookup wires, why not put BOTH of them on the car?

Now I have a double BEEP-BEEP (or is that four BEEP-BEEP-BEEP-BEEP?) horn setup. Mounted the right (passenger) side on the inner of the two horn holes (the double large/small) on the front of the fender. Positions the front of the horn just behind the inboard round hole for the light assemblies. Not as easily seen as the driver side, but it's there!

Can't tell much about the extra sound. I hit the horn button but by the time I ran around to the front of the car, the horn had quit blowing and the sound was gone! DAMN! It's about like checking your brake lights. By the time you get back there, they are off! Gahhh......

[72Rdrnner]

Now I have a double BEEP-BEEP (or is that four BEEP-BEEP-BEEP-BEEP?) horn setup.

Good idea but didn't work out. My daughter came over and we did a "sound test". Came to the conclusion no matter how hard you try, no matter how many times you twist that adjuster back and forth...

YOU CANNOT MAKE TWO ROADRUNNER HORNS SOUND THE SAME!

So I'm back to my original ONE horn!

Gahhh...............

Probably why Ma Mopar only put ONE on a Roadrunner!

[CtownRunner]

I never heard about a horn adjuster. Tell me more. Mine sounds kinda tinny and weak. I take it the round button/nob in the middle of the decal is the adjuster?

Something new every day. LOL

[72Rdrnner]

I never heard about a horn adjuster. Tell me more. Mine sounds kinda tinny and weak. I take it the round button/nob in the middle of the decal is the adjuster?

Something new every day. LOL

That's it. Looks kind of like a Torx bit would fit on it, but it won't! A small 12 point socket works best, but I can't remember which size. It will be really hard to turn as it's a tight thread fit. That way it stays where you put it. Just tweak it in or out and the sound will change.

Unless you have really long arms, you'll need someone to help!

One other thing...if you do it on a workbench, it will sound differently in the car. Being attached to the body changes the sound, even closing the hood may alter it slightly.

I spent the better part of an hour trying to "tune" the pair I put in my car, and finally gave up! Just went back to the single one!

[72Rdrnner]

I would suggest everyone also mention at which plant their car was built and what the build date was. It's possible it varied by plant or was a mid year change....

Good point, never thought about that. Mine was built in St Louis, June 20, 1972, 9:53 AM or so the build sheet says. VIN sequence number is 214743 which I understand means it was the 114,742nd car that rolled out of St. Louis that year.

Also I wonder if export or Canadian built cars might have had different locations due to the specs for a given country?

This is the kind of stuff that makes having an older car fun! Not to mention the old chicks who really dig me at the local Sonic! They and the car only get better with age! Like a fine wine or a cold beer! Let's see, older woman, fine wine and a cold beer....It just does not get any better than that!

[72Rdrnner]

What I meant in saying that neither side of the Year One harnesses had a horn wire was my engine harness is for a 72 and goes to the right side of the car and since the horn is on the left side shouldn't have a horn wire and it doesn't.The forward light harness that goes to the left is for a 71 to accommodate my 71 parking lights and doesn't have the horn wire since a 71 horn is on the right side,I think.

On the 71 harness the wire coming out of the firewall block that should be for the horn is black and has a cup on the end.It looks like it should attach to the proportioning valve.I am thinking I can wire the horn off of that.

While we are talking about horns,is the little screw on the horn to adjust the tone?

Yes, see my other post about that.

It may be the '71 horn wire was a part of the engine harness and the '72 was a part of the forward light harness. There were long bracket horns and short bracket horns, plus some had the horn relay at the horn itself, and others it was a part of the fuse block on the inside of the firewall. I don't know what years did it which way but that might explain some of the differences we're seeing.

Also I've seen some (don't remember the year exactly) that had the horn mounted aft of the radiator support on the side wall of the engine compartment. I think this was before they put the charcoal emission cannister on them as that was where the horn was mounted. Again, don't know what years those may have been.

[72GY9Runner]

The torx adjuster doesn't change the tone, it is just to adjust for sound clarity or lack of sound all together. No matter how many times you twist on that screw the tone will be basically the same. I read this in a service manual recently, and was able to get my horn to sound alot louder by tweaking it a bit.

In response to an earlier post, my car was built in the Windsor Ontario plant on March 1972. Any idea when they stopped producing 72 model year cars? This seems a bit late doesn't it?

[Eric]

usually end of model year is in June

[rr6pak]

My horn is mounted on the passenger side. Built in St. Louis on Oct 12, 1970

[72Rdrnner]

usually end of model year is in June

Mine was built 6-20-1972. Interestingly enough the casting date on the block is May 1972 but the block numbes are 1973. My best guess is the foundry had already converted over to the 1973 production, but really have no conclusive proof of that.

[Eric]

usually end of model year is in June

Mine was built 6-20-1972. Interestingly enough the casting date on the block is May 1972 but the block numbes are 1973. My best guess is the foundry had already converted over to the 1973 production, but really have no conclusive proof of that.

That's not too uncommon. A buddy of mine has a 71 runner with the numbers matching 383 block which has a casting date of 1968!!!

[roelbest]

Mine is an export car ( Germany), unrestored, horn is pass. side.
Built at St Louis, 6-9-72

[71440 gtx]

i just look at a 1972 charger 4002bbl se today in junk yard the one horn on pass side and one horn on driver side and it also had an inside chrome release handle for the hood.