horn relay question
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
horn relay question
What is anyone doing for a source on horn relays? Please tell me you are not spending $250 for an NOS part. 
Any reason why a relay from a 71 won't work on a 72?
Any reason why a relay from a 71 won't work on a 72?
Pro
Joined: Feb 2009
Posts: 589
Likes: 1
From: PA
My guess is it would be the same from 68 to ???? Make a couple phone calls to parts stores and the Corvette parts houses. Maybe you did that already, but you don't need a N.O.S. relay and I'm sure you already come to that conclusion. I gather you been checking ebay and the other web sites.
Pro
Joined: Feb 2009
Posts: 589
Likes: 1
From: PA
I just looked at one of my mail order catalogs. I grabbed Eklers as it was on top. Anyway they have the 68 to 82 horn relays. #20493 is 68 to 71 w/buzzer for $57.99. 74 to 82 for $11.99. Awwww I see there is no listing for 72 and 73. Oh oh, better call and ask them or some other Corvette house, will a 71 work. Or the 74. I don't see wy either of them wouldn't work. You might have to spice in a different plug end on your wires. I'm sure all this has been dancing around in your head.
Le Mans Master
Joined: Jan 2007
Posts: 5,485
Likes: 7
From: Peekskill NY
I just looked at one of my mail order catalogs. I grabbed Eklers as it was on top. Anyway they have the 68 to 82 horn relays. #20493 is 68 to 71 w/buzzer for $57.99. 74 to 82 for $11.99. Awwww I see there is no listing for 72 and 73. Oh oh, better call and ask them or some other Corvette house, will a 71 work. Or the 74. I don't see wy either of them wouldn't work. You might have to spice in a different plug end on your wires. I'm sure all this has been dancing around in your head.
68-71 $52.50
72-73 89.00
74-78 10.50
79-82 10.50
These are from last years catalog I have here at the office.
Go to their site for current prices.
Pro
Joined: Feb 2009
Posts: 589
Likes: 1
From: PA
Yep, he can do that as long as the points aren't gone.
Corvette world has your relay they list it as 68 to 71 w/buzzer for $49.99. 72 to 73, $59.99. 74 to 82 $15. Give Corvette World a call at 1-800-327-0185. They're nice people, their business is about 5 minutes from us.
Corvette world has your relay they list it as 68 to 71 w/buzzer for $49.99. 72 to 73, $59.99. 74 to 82 $15. Give Corvette World a call at 1-800-327-0185. They're nice people, their business is about 5 minutes from us.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
You haven't lost anything if you open up the one you have and screw it up...have you? Just bend the tabs on the cover up (underneath) and take the cover off. Now, get some wet/dry sandpaper (use it dry), fold a little piece in half, stick it in one contact set, and slide back and forth to clean up the contacts. Do the same with all contact sets. Check to see of the coil wires are intact and connected to terminal posts. If any are separated/broken/melted, just solder in a small jumper wire between the loose ends. When you are done with that, use an ohmeter to see if you have continuity on each coil. If you do, put the unit together and run it for another 35 years! If you can't repair your unit...THEN you order another one.
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Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
Thanks for all the excellent advice and support. I am going to take it off the car now and try to clean it up.
But I would still like to know if a relay from a 71 would work as well and would be completely compatible.
But I would still like to know if a relay from a 71 would work as well and would be completely compatible.
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
The 72 relay has a plug specific nylon housing with an opposite spade housing on the harness.
Also, as you know, the 72-73 has a threaded hot terminal that the wiring harness ring terminals go on and are held in place with a nylon lock nut.
The 71 relay does not have that threaded hot terminal. It has multiple spade terminals on the bottom.
cc
Last edited by CCrane65; Mar 30, 2009 at 06:53 PM.
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
cc
Last edited by CCrane65; Mar 30, 2009 at 06:52 PM.
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
Lots of great experience and information here.
Anyone know why the 72 relays are discontinued while the others seem to be easily accessible?
Anyone know why the 72 relays are discontinued while the others seem to be easily accessible?
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
cc
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
I tested the relay on a 12 volt supply. It works fine. I have the original rag joint (the one with wire pieces running through it). And it looks like all the parts in the column are there. I took it apart down to the hub assembly and the lower contact assembly. I can see nothing wrong or missing.
I have looked at the fuses underneath (not an easy task for an old fat guy). The white lettering on the fusebox is so faded that I can't read it. Does anyone know for sure which fuse is for the horn? 72 smallblock, manual, a/c.................
I have looked at the fuses underneath (not an easy task for an old fat guy).
The white lettering on the fusebox is so faded that I can't read it. Does anyone know for sure which fuse is for the horn? 72 smallblock, manual, a/c.................
Last edited by brdd; Mar 31, 2009 at 02:56 PM.
Burning Brakes
Joined: Jun 2008
Posts: 1,086
Likes: 1
From: Michigan
If your horn is inop read Jim Shea's paper on horn diagnostics. You will zero in on the issue very quickly.
http://jimshea.corvettefaq.com/?page_id=4
http://jimshea.corvettefaq.com/?page_id=4
Thread Starter
Melting Slicks
Joined: Apr 2002
Posts: 3,268
Likes: 2
From: Minnesota in the summer, Las Vegas in the winter
Yes I have tested the (new) horn. It works all the way back to the relay so I do know that the (green) horn wire is good inside the harness from the relay to the horn. That is where I started........testing the horn itself.
If I assume that the horn wire from the relay to the harness mount on the firewall is good, then it must be within the column, or else a ground on the column (?).
I very much appreciate each and every reply here. I read them all and I am grateful for all these teachers for one student.
If I assume that the horn wire from the relay to the harness mount on the firewall is good, then it must be within the column, or else a ground on the column (?).
I very much appreciate each and every reply here. I read them all and I am grateful for all these teachers for one student.
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
Have you tried removing the horn button and using a screwdriver to short the horn contact to the steering wheel?
Also, when you press the button, do you hear anything at all like the relay clicking?
cc
Also, when you press the button, do you hear anything at all like the relay clicking?
cc
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
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.