66 horn problem
Thread Starter
Heel & Toe
Joined: Jan 2008
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From: Bonita,Ca.91902;Palm Desert,Ca.92211; Reinholds,Pa.17569
66 horn problem
I have no sound from my horns. I bypassed the wiring and direct wired both horns. Pass. side works, driver's side not working. I guess this means I need a rebuild on the driver's side horn. Next, when I press the horn button I have a buzzing sound in the horn relay. Does this indicate a good horn relay? If not, what test can I perform to tell if the relay is functioning properly? There is no power to the green wire at the horn. What is the most likely source of the problem ? Lastly, does the cover pull off of the relay exposing a bolt or screw holding the relay in place? Thanks in advance for your help.
Craig
Craig
Le Mans Master
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From: Going too fast over the hill. Iowa
the bolt holding it to the rad support is below the relay cover - leave the cover on. Disconnect the battery before removing the relay.
to test the harnesses: unplug the T shaped plastic connector. With an ohmmeter red lead connected to the black wire in the T connector and the ohmmeter black lead grounded, there should be zero ohms when the horn button is pressed and infinite ohms otherwise. Connecting a jumper wire from the battery 12volts to the green wire in the T connector should blow the horns. If both wires pass the tests, replace the relay. If the old one is original, save it. It's date coded.
PS - I am refering to the ohmmeter mode of a small $3 multimeter when I refer to an ohmmeter. If you don't have one, you can ususally find one on sale at a tool store like Harbor Freight.
to test the harnesses: unplug the T shaped plastic connector. With an ohmmeter red lead connected to the black wire in the T connector and the ohmmeter black lead grounded, there should be zero ohms when the horn button is pressed and infinite ohms otherwise. Connecting a jumper wire from the battery 12volts to the green wire in the T connector should blow the horns. If both wires pass the tests, replace the relay. If the old one is original, save it. It's date coded.
PS - I am refering to the ohmmeter mode of a small $3 multimeter when I refer to an ohmmeter. If you don't have one, you can ususally find one on sale at a tool store like Harbor Freight.
Last edited by magicv8; Sep 12, 2008 at 04:51 PM. Reason: ps
Thread Starter
Heel & Toe
Joined: Jan 2008
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From: Bonita,Ca.91902;Palm Desert,Ca.92211; Reinholds,Pa.17569
Checked the green wire from relay to horns and it's ok. We have a multimeter. When we select 200 ohms we get a 23.5 reading . With horn button depressed we get as low as a 6 reading. Does this mean that relay is bad ? Lousy ground ? Thanks again.
Safety Car
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Easy test. Remove the plugs from the #2 and #3 terminals. Take a jumper wire and go from the #2 terminal on the relay (black wire) to battery ground. Using a test light, put the alligator clip on battery ground and touch the probe to the #3 terminal (dark green). Bulb in the test light should glow if the relay is good.
Not much to see or do under the cover, except you might see that the contacts are burnt.
If you want to try fixing the horn yourself, here is a link....courtesy of BarryK.....
Corvette Horn Repair
Not much to see or do under the cover, except you might see that the contacts are burnt.
If you want to try fixing the horn yourself, here is a link....courtesy of BarryK.....
Corvette Horn Repair
Thread Starter
Heel & Toe
Joined: Jan 2008
Posts: 24
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From: Bonita,Ca.91902;Palm Desert,Ca.92211; Reinholds,Pa.17569
Tim,
Thanks for the excellent photos and instructions for test. We have current using your test and therefore conclude that the relay is ok. Still don't have horns. I was wondering if maybe the wiring is incorrect . My relay is a little different than the one you pictured. My #2 post has the green wire attached,# 3 has nothing . If you're looking at the first picture of the relay you posted the far right screw has two wires attached ; red, and black & white. The left screw has nothing attached.My relay has a # 4 post (it's below the outer right screw in the relay assembly near the bottom right of the assembly) To it is attached the black wire.Any ideas ? I don't want to cause a short by moving the black wire to the # 3 post without knowing this is correct. Thanks again for the help. This shouldn't be this difficult.Also thanks for the link for the horn rebuilt kit, I'm ordering one today.
Craig
Thanks for the excellent photos and instructions for test. We have current using your test and therefore conclude that the relay is ok. Still don't have horns. I was wondering if maybe the wiring is incorrect . My relay is a little different than the one you pictured. My #2 post has the green wire attached,# 3 has nothing . If you're looking at the first picture of the relay you posted the far right screw has two wires attached ; red, and black & white. The left screw has nothing attached.My relay has a # 4 post (it's below the outer right screw in the relay assembly near the bottom right of the assembly) To it is attached the black wire.Any ideas ? I don't want to cause a short by moving the black wire to the # 3 post without knowing this is correct. Thanks again for the help. This shouldn't be this difficult.Also thanks for the link for the horn rebuilt kit, I'm ordering one today.
Craig
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I'm not sure about the vett because my horns aren't origional.
But.. I do remember that you could adjust the sound/pitch of older car horns by moving a screw in or out on the horn. I think it was up against a diaphram or ???. Your horn may be out of adjustment. Look for a small screw, 8-32, 10-32 and tweek it. John
But.. I do remember that you could adjust the sound/pitch of older car horns by moving a screw in or out on the horn. I think it was up against a diaphram or ???. Your horn may be out of adjustment. Look for a small screw, 8-32, 10-32 and tweek it. John
Safety Car
Joined: Feb 2006
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Craig....does your relay look like this?
Mid years didn't have the #4 terminal originally. It appears the aftermarket is using generic relays. Apparently this terminal has something to do with a buzzer that sounds when you have the key in the ignition. The picture below is from Standard Brands and has a small schematic.It appears that the #2 terminal is the same ( black wire which grounds at the horn button). but the old #3 terminal is now #1, green wire to horns.
So here is how I believe it should be hooked up.
Green wire to #1.
Black wire to #2.
Nothing on #4.
Just go slow when connecting the terminals...in case I got this bass ackwards.
Mid years didn't have the #4 terminal originally. It appears the aftermarket is using generic relays. Apparently this terminal has something to do with a buzzer that sounds when you have the key in the ignition. The picture below is from Standard Brands and has a small schematic.It appears that the #2 terminal is the same ( black wire which grounds at the horn button). but the old #3 terminal is now #1, green wire to horns.
So here is how I believe it should be hooked up.
Green wire to #1.
Black wire to #2.
Nothing on #4.
Just go slow when connecting the terminals...in case I got this bass ackwards.
Thread Starter
Heel & Toe
Joined: Jan 2008
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From: Bonita,Ca.91902;Palm Desert,Ca.92211; Reinholds,Pa.17569
Tim,
Thanks again. What you said makes sense since the key buzzer alarm system started in 67. I bought my car about two months ago completely restored and a lot of the parts are aftermarket. I called the local Chevy dealer today and the original delco-remy part is still available so I'm picking it up tomorrow and I'll see how that compares to the one I have.(mine is the one you pictured with the #4 terminal) Your proposed wiring scheme is exactly how I thought it should be wired but didn't have the huevos to try. I don't want to turn a $ 35 problem into a $ 5,000 problem . Tomorrow I'll look at the Delco Remy and if it's like the one in your first photo I'll put that one in and try it. If not I'll use an extra battery for the power source and try getting my one so-so working horn to sound. Ordered the horn rebuild kit today from Zip, thanks. ( GM wanted $47 per horn for re-build kit) GM was way cheaper than the repro places for the relay. Go figure. I'll post up my findings, maybe someone else will gain something useful from this exercise. I know that I get a lot of information reading about problems for which other owners have sought help.
Craig
Thanks again. What you said makes sense since the key buzzer alarm system started in 67. I bought my car about two months ago completely restored and a lot of the parts are aftermarket. I called the local Chevy dealer today and the original delco-remy part is still available so I'm picking it up tomorrow and I'll see how that compares to the one I have.(mine is the one you pictured with the #4 terminal) Your proposed wiring scheme is exactly how I thought it should be wired but didn't have the huevos to try. I don't want to turn a $ 35 problem into a $ 5,000 problem . Tomorrow I'll look at the Delco Remy and if it's like the one in your first photo I'll put that one in and try it. If not I'll use an extra battery for the power source and try getting my one so-so working horn to sound. Ordered the horn rebuild kit today from Zip, thanks. ( GM wanted $47 per horn for re-build kit) GM was way cheaper than the repro places for the relay. Go figure. I'll post up my findings, maybe someone else will gain something useful from this exercise. I know that I get a lot of information reading about problems for which other owners have sought help.
Craig
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Thread Starter
Heel & Toe
Joined: Jan 2008
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From: Bonita,Ca.91902;Palm Desert,Ca.92211; Reinholds,Pa.17569
I picked up the Delco from the local Chevy dealer. When I called for the part I didn't ask for it by the original part number. This is replacement part # 12339243, very slightly different than the original and now powering my one working horn. I stand corrected on 69 as the first year for the buzzer system . Thanks to all who helped me on this .
Craig
Craig
Limping across the line
Joined: Oct 2002
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From: Peoria Az
I'm not sure about the vett because my horns aren't origional.
But.. I do remember that you could adjust the sound/pitch of older car horns by moving a screw in or out on the horn. I think it was up against a diaphram or ???. Your horn may be out of adjustment. Look for a small screw, 8-32, 10-32 and tweek it. John
But.. I do remember that you could adjust the sound/pitch of older car horns by moving a screw in or out on the horn. I think it was up against a diaphram or ???. Your horn may be out of adjustment. Look for a small screw, 8-32, 10-32 and tweek it. John
NO No No Dont adjust the screw on the horn unless you have a Ammeter and know what they should be set at. When set to the proper amp draw the horns give off the note they should
