horn relay question
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
There are several possible 'fault' areas beyond the horn contact ring...and before the horn relay. Wires can get pinched/broken/shorted; connector pins can vibrate out-of-contact/corrode; and the relay can fail. You state that there is continuity in the relay...but will it pass significant current to activate the horn? Pull the feed line from the horn contact from the relay and then ground that pin to complete the circuit (with key "on"). The horn should work, if the relay is good. If so, then..you are correct...it is in the column and/or the electrical path to the relay. Remember that there is a firewall bulkhead connector unit that is just a bunch of connections from wiring in the cockpit to wiring in the engine compartment. Those have no trouble failing, either. See if the ground connection at the horn ring is viable. Disconnect the signal connector at the relay but 'lock' the horn ring down so that the ground connection is present [trying to signal the relay]. Now, use your ohmeter to test various points along the signal line path until you find that you have "lost" the ground signal. That will be the area of your problem. Good luck on the search. 
Especially with the black wire contact on the relay. I found mine to be quite rusted. I cleaned both contacts with emery cloth and it works like a charm.Also brdd, to answer your question earlier about which fuse is the horn fuse, there isn't one in the fuse panel ostensibly because from the steering column to the relay is simply a ground wire that completes the circuit when the button is pressed. All the action takes place at the relay.
cc
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
I have tried that, no dice. No clicking sound when the horn button was pushed..........
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
Also brdd, to answer your question earlier about which fuse is the horn fuse, there isn't one in the fuse panel ostensibly because from the steering column to the relay is simply a ground wire that completes the circuit when the button is pressed. All the action takes place at the relay.
cc
cc
And I find out how little I really do know...........
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
You should also check the continuity of your ground wire from the horn button to the relay with a digital voltmeter. As long as it test as a complete circuit the wire is good.
My money is on the relay contacts.
cc
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
Not the relay. When I had it out I hooked up a 12 volt power supply to it and it works fine. This weekend I will have some time to start searching through the column.
Any other ideas, please post 'em.
Any other ideas, please post 'em.
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
Safety Car
Joined: May 2006
Posts: 3,732
Likes: 709
From: Shelton, Connecticut
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Find a junk yard
If you have a junk yard that lets you pick your parts, you will find that the horn relay for almost any Chevy will be the same p/n as the Vette. These were not Corvette unique parts.
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
The 1972-73 Corvette relay is unique even among Corvette parts.
You seem to forget about the lack of a body ground on Corvettes. Meaning each electrical part must have a ground terminal or common source.
cc
Last edited by CCrane65; Apr 2, 2009 at 02:43 PM.
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Burning Brakes
Joined: Jun 2008
Posts: 1,086
Likes: 1
From: Michigan
This would surprise me very much. Just a quick search showed that the 1972 Chevelle shared a horn relay with the 1973 Nova but no mention of any year Corvette.
The 1972-73 Corvette relay is unique even among Corvette parts.
You seem to forget about the lack of a body ground on Corvettes. Meaning each electrical part must have a ground terminal or common source.
cc
The 1972-73 Corvette relay is unique even among Corvette parts.
You seem to forget about the lack of a body ground on Corvettes. Meaning each electrical part must have a ground terminal or common source.
cc
I have found this relay to be available and have found another GM car that shares the same relay. Anyone want to take a guess? If you have access to a junk yard the alternate part shouldn't be hard to find. I also have the OEM part number and AC Delco part numbers. There are actually three Delco part numbers that will work.
PM me if you want some additional info.
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
Does the black wire thread through the main harness? Where does it go when it leaves the relay?
I'm sorry I can't get to my car outside right now . My wife is handicapped and today is just one of those days, so I am inside for the day.
But I do appreciate every answer. This information is helping me for the weekend. My son will be in town and so we will get some "car time" on Saturday.
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
I was guessing that the black wire was the one from the relay to the horn. Now I remember that it is green coming out at the horn.
Does the black wire thread through the main harness? Where does it go when it leaves the relay?
I'm sorry I can't get to my car outside right now . My wife is handicapped and today is just one of those days, so I am inside for the day.
But I do appreciate every answer. This information is helping me for the weekend. My son will be in town and so we will get some "car time" on Saturday.
Does the black wire thread through the main harness? Where does it go when it leaves the relay?
I'm sorry I can't get to my car outside right now . My wife is handicapped and today is just one of those days, so I am inside for the day.
But I do appreciate every answer. This information is helping me for the weekend. My son will be in town and so we will get some "car time" on Saturday.
When you press the horn button it completes the circuit by grounding out the relay creating the 12 volt feed for the horn.
cc
Last edited by CCrane65; Apr 2, 2009 at 10:02 PM.
Burning Brakes
Joined: Mar 2004
Posts: 816
Likes: 1
From: Finland
I would tend to agree with CCrane here. I have a '73 and have done a lot of searching for a horn relay. The problem is that the '73 relay has a big honkin' exposed stud that is hot 12v all the time. If you short it out you will shut down the entire car and burn out the fuseable link.
I have found this relay to be available and have found another GM car that shares the same relay. Anyone want to take a guess? If you have access to a junk yard the alternate part shouldn't be hard to find. I also have the OEM part number and AC Delco part numbers. There are actually three Delco part numbers that will work.
PM me if you want some additional info.
I have found this relay to be available and have found another GM car that shares the same relay. Anyone want to take a guess? If you have access to a junk yard the alternate part shouldn't be hard to find. I also have the OEM part number and AC Delco part numbers. There are actually three Delco part numbers that will work.
PM me if you want some additional info.
