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Discussion Starter #1
Hey I have a 70 SS and according to my electrical schematic I should have a black wires going to the horn relay. Recently I found that whom ever owned this car b4 put a 72 wiring harness in car, there was no horn relay so I am now trying to hook it back up because horn dosent work. They had a green wire spliced into the horn with no relay. relay is necessary right? also which wires hook upto the horn relay and what orders. please help :confused: thanks steel
 

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Yes the relay is needed. Which harness is the 72 harness? Just the dash harness, the harnesses under the hood, or both?
On a 70 the black horn wire was in the outer bulkhead connector (lamp harness), while the 72 had the black horn wire on the inner bulkhead connector (engine harness). The 72 harness black horn wire had a connector on it and only comes out of the bulkhead about 6 inches.
 

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Discussion Starter #3
john, it looks like both dash and engine, do you know on a 72 harness, you said the wire came out black for 6 inches what color then? which wires go where on relay, my relays marked 2,3,4,5.
thanks steel
 

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The 72 engine harness didn't use the relay you have. Both the small black wire and the green horn wire plugged into it. The horn relay was mounted next to the brake booster. That's why the black horn wire was only about six inches long.
I'm not ducking all of your questions. Just trying to see what someone has done. If that car has a true 72 engine harness, there should be a large red wire coming up from the starter and end up around the brake booster. Someone must have tied it together with a wire from the alternator near the brake booster.
 

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Don't know where to hook it up to because I can't tell (so far) where all the wires are.
 

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Not much for me to find. The wires are on your car. It's a little difficult to hook up a relay on modified wiring without knowing where the wires are. That's why I keep asking questions.
 

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Discussion Starter #9
John it is a 72's wiring I found the horn relay behind the master cyclinder. why would someone do this? Is this the first year for HEI? steel
 

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Nope not the first year for HEI. The 72 was a points car. Guess it was time for a wiring change in the car..or bored engineers.
So there's a large red wire tied to a stud on the 72 style horn relay? There are 2 places on the bottom of the relay for connectors. One is for the green wire that goes to the horn. The other is for that short black horn button wire that runs into the bulkhead connector.
 
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