1974 Imperial Horn Relay Help

CollinR

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Hello C-Bodies! It's Collin here. I recently took my 1974 LeBaron in for an electrical issue that was causing the door ajar buzzer to sound constantly which also disabled the horn. I was called by the shop and told that the relay switch was done for and was therefore disconnected to prevent the further buzzing sound. They were unable to locate a replacement and said that if I were to find one they would install it for me. Can anyone give me some suggestions on how to move forward or point me in the right direction of finding that part? At the moment I have no horn and my chronometer doesn't work. I have one of the older style rubber rings on my steering wheel that activates the horn. Any help would be greatly appreciated!
 

Big_John

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Rock Auto shows a replacement.

But... The standard procedure was to bend or clip the tab that controls the buzzer.... and plug the relay back in. Honk horn as needed.
 

CollinR

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I tried sending them that part however they said that it is the incorrect one unfortunately. I guess the prong count was incorrect for the one I had. The Rock auto Relay has three prongs and mine has two. They said they would be unable to clip the tab due to the entire relay being shot. I guess I'll have to drive without a horn till I can locate the correct part!
 

CBODY67

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IF the horn contact ring is still soft, then squeeze it hard to see if the horn works. Check the old horn relay itself, taking the top off, to see if it is crispy-crittered inside. IF it is crispy in theree, that means the horn switch in the steering wheel is shorted and honked the horn until the horn relay failed . . . or somebody unhooked the horn. Went through this on the Rim Blow steering wheel on my '70 Monaco Brougham.

ALSO . . . remove the steering wheel and check the tension on the horn contact on the turn signal switch! IF the horn honked long enough to fry the horn relay internally, then the spring which holds the contact against is rubbing contact on the steering wheel item will be weak enough to let it fall back into its holder. NOT making contact! New turn signal switch will be needed. Did that deal, too, on my '70 Monaco Brougham Rim Blow steering wheel.

Start looking for a later model year steering wheel with a normal horn pad that will fit your steering column. Paint to match. No more horn issues, I suspect.

Happy Holidays!
CBODY67
 

CollinR

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This is the relay switch it needs (had). It's unlike most of the Mopar switches I have seen so it leads me to believe the Imperials received a unique relay.

thumbnail.jpeg
 

Boydsdodge

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My 73 Imperial is constantly buzzing with keys in or out until I buckle the seet belt. When I am working on the car I remove the relay.
Not that this will help you out, just thought I would share what my relay looks like.

IMG_2595.jpeg


IMG_2596.jpeg


IMG_2597.jpeg
 

CollinR

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That's the insane thing that confuses me. All of the Imperial relays I see look just like yours. They have a three or four prong configuration. My two prong relay is very strange and I cannot find the part numbers anywhere online. The shop just disconnected it instead of hassling with it further. They said if I can find that part they will install it but that's looking unlikely.
 
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Big_John

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This is the relay switch it needs (had). It's unlike most of the Mopar switches I have seen so it leads me to believe the Imperials received a unique relay.

View attachment 570834
I tried to look up that number in the parts book and could not find that number. Having the two tabs instead of three is the first thing I noticed... In the horn relay/key buzzer, there are two tabs for the relay and one for the buzzer.

So... I looked up the horn relay part number and it's the same across the board for ALL the c-bodies in 1974. 3764643 is the correct number.

I'm really not sure what that piece they took out is.

1670443675004.png
 

CollinR

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I'll have to ask.. this is why it sucks to not have the technical knowledge like a lot of you guys do to work on these things yourselves. I have to rely on what I am told when I take it in.
 

War Wagon2

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Hi CollinR Reading about your initial complaint , I see it not making any sense , the item you show in your photo (3764548) is the Key/In seatbelt buzzer. Your horn relay is mounted on the relay block near the fuse block and is a metal can design. There are a few differences in that relay , IF you have the New York city Horn option then you will have a five terminal relay. If not, you will have the conventional three terminal as shown by Big John (P/N 3764643 ). The little yellow buzzer you show is activated either by the Key switch in the column or by the seat belt interlock module. The interlock module reacts to two switches in the seat , either a beam switch right under your Derrier or by the seat belt switch in the buckle. You will get a buzzer operation and a seat belt warning light until you fasten your belt ,then it should shut up. Door Adjar Buzzer operation and the door Adjar light is activated by a set of switches mounted on the door frame of each door. They are those black button like things , the same annoying buzzer is used with activation origin from the seat belt interlock module. So in short the seat belt Buzzer is a separate entity from the horn. So why does your Chronometer not work? Well its fed by the same fuse that feeds the Horn , so you need to check cavity no. 4 in the fuse box to see if the fuse is intact, if not , that's why your horn no longer works and something caused it to blow. Your seat belt buzzer etc. is fed from fuse cavity 5. The door Adjar switches have one wire going to them with the case grounded by the mounting screws. So you see they are two separate entities.
So...reconnect the buzzer and then go around to each door Adjar switch and remove the small Phillips screws and pull out the switch just a bit so the contact to ground is broken the buzzer should shut up , re install the screws/ switch one at a time to isolate the culprit.
With that out of the way you can concentrate on the Horn. The reason you could not locate a replacement Buzzer is that Chrysler would stamp a part number on the buzzer or relay as a "production number" To locate the part you had to have the "service" number in each parts book there was a table giving you a cross reference from production to service numbers.
 

Toolmanmike

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Hi CollinR Reading about your initial complaint , I see it not making any sense , the item you show in your photo (3764548) is the Key/In seatbelt buzzer. Your horn relay is mounted on the relay block near the fuse block and is a metal can design. There are a few differences in that relay , IF you have the New York city Horn option then you will have a five terminal relay. If not, you will have the conventional three terminal as shown by Big John (P/N 3764643 ). The little yellow buzzer you show is activated either by the Key switch in the column or by the seat belt interlock module. The interlock module reacts to two switches in the seat , either a beam switch right under your Derrier or by the seat belt switch in the buckle. You will get a buzzer operation and a seat belt warning light until you fasten your belt ,then it should shut up. Door Adjar Buzzer operation and the door Adjar light is activated by a set of switches mounted on the door frame of each door. They are those black button like things , the same annoying buzzer is used with activation origin from the seat belt interlock module. So in short the seat belt Buzzer is a separate entity from the horn. So why does your Chronometer not work? Well its fed by the same fuse that feeds the Horn , so you need to check cavity no. 4 in the fuse box to see if the fuse is intact, if not , that's why your horn no longer works and something caused it to blow. Your seat belt buzzer etc. is fed from fuse cavity 5. The door Adjar switches have one wire going to them with the case grounded by the mounting screws. So you see they are two separate entities.
So...reconnect the buzzer and then go around to each door Adjar switch and remove the small Phillips screws and pull out the switch just a bit so the contact to ground is broken the buzzer should shut up , re install the screws/ switch one at a time to isolate the culprit.
With that out of the way you can concentrate on the Horn. The reason you could not locate a replacement Buzzer is that Chrysler would stamp a part number on the buzzer or relay as a "production number" To locate the part you had to have the "service" number in each parts book there was a table giving you a cross reference from production to service numbers.
Wow, turn down the volume please. The bold text hurts my eyes! :lol:
 

CollinR

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Hi CollinR Reading about your initial complaint , I see it not making any sense , the item you show in your photo (3764548) is the Key/In seatbelt buzzer. Your horn relay is mounted on the relay block near the fuse block and is a metal can design. There are a few differences in that relay , IF you have the New York city Horn option then you will have a five terminal relay. If not, you will have the conventional three terminal as shown by Big John (P/N 3764643 ). The little yellow buzzer you show is activated either by the Key switch in the column or by the seat belt interlock module. The interlock module reacts to two switches in the seat , either a beam switch right under your Derrier or by the seat belt switch in the buckle. You will get a buzzer operation and a seat belt warning light until you fasten your belt ,then it should shut up. Door Adjar Buzzer operation and the door Adjar light is activated by a set of switches mounted on the door frame of each door. They are those black button like things , the same annoying buzzer is used with activation origin from the seat belt interlock module. So in short the seat belt Buzzer is a separate entity from the horn. So why does your Chronometer not work? Well its fed by the same fuse that feeds the Horn , so you need to check cavity no. 4 in the fuse box to see if the fuse is intact, if not , that's why your horn no longer works and something caused it to blow. Your seat belt buzzer etc. is fed from fuse cavity 5. The door Adjar switches have one wire going to them with the case grounded by the mounting screws. So you see they are two separate entities.
So...reconnect the buzzer and then go around to each door Adjar switch and remove the small Phillips screws and pull out the switch just a bit so the contact to ground is broken the buzzer should shut up , re install the screws/ switch one at a time to isolate the culprit.
With that out of the way you can concentrate on the Horn. The reason you could not locate a replacement Buzzer is that Chrysler would stamp a part number on the buzzer or relay as a "production number" To locate the part you had to have the "service" number in each parts book there was a table giving you a cross reference from production to service numbers.
Brilliant answer. Thank you very much.
The photo I posted was what they sent to me in an email and they called it a horn relay. I will try and give this info to the shop and see what I can do with the information. I really appreciate all of you gentleman helping me with this issue.
 
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CollinR

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War Wagon2, I sent your quote in an email to the shop. It is one of the very few shops here in Middle TN that actually work on these old vehicles as most I have been to have turned me down due to it being too complicated of a car for them to deal with. For further reference, seeing as how they took out an incorrect relay (from the seat). Where is the actual horn relay located in my Imperial?
 

War Wagon2

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Hi Again! First I should apologize for the bold type in my last messages (apparently Bold means I'm yelling or something like that) I'll watch that in future! So.. your horn relay is mounted on a relay bank panel on the left side of the steering column just above the fuse panel. The fuse panel is on a hinged bracket with small thumb screw , with a turn of that, the fuse box can be lowered , then look up you'll see a gray plastic panel , its held in place with a push-on bracket , pull the the bank straight back and then you can lower it for servicing. With the bracket slot facing up , the horn relay is below the four way flasher and between a larger relay which is the A/C blower relay and a cylindrical relay which is your ignition switch illumination time delay relay.
 

Boydsdodge

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I remember finding the NY horn option in the books when I worked at the dealer. I will try to look it up and see if it is in the service or parts manual.
 

Boydsdodge

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I know we are talking 74. my 73 has the gold metal case relay the buzzes anytime you open the door and if I remove it I will loose horn function. This is correct and should it buzz all the time?
 

ynst

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An old rim-blow horn, eh?
Tilt column as well?

If it's a tilt column, chances are it'll be a Saginaw column sourced through GM (Chrysler didn't make tilt columns back then) and will have an adapter harness between the Saginaw turn signal switch pigtail and the Imperial body harness.

Probe the black wire at one end of the turn signal plug and see if it grounds when you squeeze the horn ring. If it doesn't, jump the black wire to ground. If the horn blows, the circuitry is ok but the rim-blow horn probably has an open circuit and you'll need to replace the steering wheel itself. If you pop off the center pad and short the horn wire to ground and the horn blows, the steering wheel is the culprit.

I ran into this issue in 1989 on an Imperial owned by Tex Smith (Hot Rod Mechanix, Custom Car, Rod Action Magazine, Hot Rod Magazine, Rod & Custom, etc). He couldn't get a state inspection on the car because the horn didn't work so I fixed it with a Radio Shack push button and he sold me the '72 Newport Custom he had bought so that Pegge could have a car to drive.

Somebody had disconnected the cruise control button and re-wired it into a plastic horn relay out on the left fender brace and, being out in the elements, it corroded and the horn quit. The plastic relay was designed to be mounted INSIDE the car on the fuse box, not out under the hood where it was subject to water intrusion.

I reconnected the cruise control and got that working again then Tex and I drove over to the local Radio Shack, bought a tiny momentary push button switch, and placed it dead center in the steering wheel pad. I could have put the button elsewhere but it was decided to put it where it should be most logically located were it be need in a hurry. It ruined the cross piece but that wasn't my decision.

The metal factory horn relay was still installed so as soon as I grounded the horn wire with the Radio Shack switch, the horn worked.

When I finished, everything was factory correct except for the added switch. Pegge was ecstatic that she had her Imperial running again and WITH cruise control to boot.

Saginaw rim-blow horns were prone to failure back then. If you have a flat, GM-style turn signal plug on your steering column, it's a Saginaw column, not a MoPar column.

BTW, that beige Newport in my avitar is the very same Newport I bought from Tex out in Idaho in '89.
 
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