Horn relay? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Earl Filter · 06-01-2005, 01:50 PM

My '77 has an underdash plug-inrelay for the horn, which works. It also has a horn relay mounted on the radiator support that doesn't work. It's rectangle, flat on the side that mounts against the support, and rounded on the other. It has 4 connections that use a screw to hold down the u-shaped wire ends. One is for ground, another gets 12V when you push the horn button. The other two go to each horn. I can't get a part number for that relay. Anyone know which one it is?

Earl Filter · 06-01-2005, 11:03 PM

Anyone?

NeCrOmAnCeR · 06-03-2005, 09:04 AM

Do you have any pictures of it? I personally have not seen one like you are describing.

One ground and a 12 voly source only when the horn button is pressed? Assumed to come from the relay under the dash? And the other two go to the two horns. Does not sound like a relay to me. A relay would have a constant 12 volt supply also. Could be some type of 'free wheel' diode assembly to keep the 'back EMF' out of the electrical system of the truck. Are these some type of after-market horns?

Earl Filter · 06-03-2005, 10:25 AM

Quote:

Originally Posted by NeCrOmAnCeR

Do you have any pictures of it? I personally have not seen one like you are describing.

One ground and a 12 voly source only when the horn button is pressed? Assumed to come from the relay under the dash? And the other two go to the two horns. Does not sound like a relay to me. A relay would have a constant 12 volt supply also. Could be some type of 'free wheel' diode assembly to keep the 'back EMF' out of the electrical system of the truck. Are these some type of after-market horns?

Yeah, I'll get a pic. When you press the horn button, the relay under the dash clicks. This "relay" clicks, too. It does not have power to it until the horn button is pressed. I looked at the parts store big book of all electrical parts, and there are several in there for GM cars that are similar, and they are called horn relays. It all looks factory (wiring in the factory loom, mounting, etc) and the horns are original. I bypassed it right now, by having the two horn wires and the 12v wire all on the same terminal on the relay. Now, when pressing the horn button, power goes from the underdash relay to the 12v power connector on the underhood relay, which in turn goes directly to the two horns. They work that way.

NeCrOmAnCeR · 06-03-2005, 10:44 AM

Sounds right. The under dash relay is the only one on my truck. I will have to try and find one to see I guess. Good luck!

06-01-2005, 01:50 PM	#1
Earl Filter Registered User Join Date: May 2005 Posts: 212	Horn relay? My '77 has an underdash plug-inrelay for the horn, which works. It also has a horn relay mounted on the radiator support that doesn't work. It's rectangle, flat on the side that mounts against the support, and rounded on the other. It has 4 connections that use a screw to hold down the u-shaped wire ends. One is for ground, another gets 12V when you push the horn button. The other two go to each horn. I can't get a part number for that relay. Anyone know which one it is? __________________ Real Name - Brandon Current Vehicles: 1977 C20 Silverado 454/TH400 3.73s 1989 Jaguar XJ6 in the middle of an LT1/4L60E swap

06-01-2005, 11:03 PM	#2
Earl Filter Registered User Join Date: May 2005 Posts: 212	Anyone? __________________ Real Name - Brandon Current Vehicles: 1977 C20 Silverado 454/TH400 3.73s 1989 Jaguar XJ6 in the middle of an LT1/4L60E swap

06-03-2005, 09:04 AM	#3
NeCrOmAnCeR Registered User Join Date: Feb 2004 Location: Hodgenville, Ky Posts: 735	Do you have any pictures of it? I personally have not seen one like you are describing. One ground and a 12 voly source only when the horn button is pressed? Assumed to come from the relay under the dash? And the other two go to the two horns. Does not sound like a relay to me. A relay would have a constant 12 volt supply also. Could be some type of 'free wheel' diode assembly to keep the 'back EMF' out of the electrical system of the truck. Are these some type of after-market horns? Last edited by NeCrOmAnCeR; 06-03-2005 at 09:05 AM.

06-03-2005, 10:44 AM	#5
NeCrOmAnCeR Registered User Join Date: Feb 2004 Location: Hodgenville, Ky Posts: 735	Sounds right. The under dash relay is the only one on my truck. I will have to try and find one to see I guess. Good luck!



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