1965 multi-function Horn Relay

[Jim B.]

This is my first original post on the Forum. While doing some trouble shooting on my non-op horns I was reviewing the schematic for the horn relay circuit. There look to be at least 3 possibly 4 hot (red) wire routes leading from the relay to the Starter Solenoid, Alternator, and Alternator Regulator. Besides serving as a high current relay operating the horns when the ground circuit is closed, what other function does the relay perform? Why so many +12vDC connectors?

Thanks in advance for your response

Jim

[Joe R.]

Re: 1965 multi-function Horn Relay

This is my first original post on the Forum. While doing some trouble shooting on my non-op horns I was reviewing the schematic for the horn relay circuit. There look to be at least 3 possibly 4 hot (red) wire routes leading from the relay to the Starter Solenoid, Alternator, and Alternator Regulator. Besides serving as a high current relay operating the horns when the ground circuit is closed, what other function does the relay perform? Why so many +12vDC connectors?

Thanks in advance for your response

Jim

Jim,
Welcome to the NCRS board! You'll find some sharp minds here even through we're getting old! To your question. The horn relay performs only one function and that's to blow the horn BUT it's also a convenient power strip to route 12 volts to other areas under the hood. The engineers simply used the convenient position to keep from running more wires from the fuse box or ignition switch. Enjoy your Corvette and if you need your horns rebuilt I would recommend Gary Steinkellner at THE HORN WORKS. WWW.CLASSICCARHORNS.COM OR 1 608 361-0095.

JR

[Gene M.]

Re: 1965 multi-function Horn Relay

The horn relay heavy wire terminal side is used as a distribution and common + connection point.

[Jim B.]

Re: 1965 multi-function Horn Relay

Thanks Joe and Gene. That makes sense now. I am trying to remove my relay to continue with my trouble shooting and a previous owner has used an incorrect standard screw fastener rather than the specified hex head type bolt fastener. I am having a very difficult time now, getting that screw to loosen up. May need to drill the thing out. I should have mentioned in my initial post this is an L78 car with the relay on the drivers side wedged in there with the voltage regulator.

Jim

[Richard M.]

Re: 1965 multi-function Horn Relay

Jim, Welcome! Great to have more members join in here on the TDB.

As far as the wiring diagram goes.....be careful. Some of the diagrams are misleading. Some show a hot wire connected to ground at the relay, or a ground connected to the buss bar. I forget which year's diagrams specifically, but the mechanical layout of the wires going to the relay terminals and buss bar can get confusing.

Rich

[Jim B.]

Re: 1965 multi-function Horn Relay

Hi Rich
Thanks for the cautionary note. My diagrams show a single black wire lead connecting to the ground post on the relay. I do however, see a reference to black/white wire lead connecting to the hot buss bar on the relay. Is that what you are referring to? For what its worth, the actual wiring on my relay seems to match what I am seeing in my diagrams.

Jim, Welcome! Great to have more members join in here on the TDB.

As far as the wiring diagram goes.....be careful. Some of the diagrams are misleading. Some show a hot wire connected to ground at the relay, or a ground connected to the buss bar. I forget which year's diagrams specifically, but the mechanical layout of the wires going to the relay terminals and buss bar can get confusing.

Rich

[Richard M.]

Re: 1965 multi-function Horn Relay

Tim, I looked up some diagrams and the Service Manual for 1963 shows the erroneous data. It shows the Blk and Tan tied together, but that's incorrect. Blk goes to the horns, Tan from the horn button, so they MUST be separate.

There's also a diagram floating around which has the grounds wrong. I looked for it briefly but couldn't find it. Someone once followed it and burned up a brand new harness.

The '65 diagram appears to be okay though. Yes the Blk/Wht goes to the buss bar and is the load sense wire for the Ammeter circuit so that is correct.

http://www.keystonestatecorvetteclub.com/Documents/Corvette%20wiring%20diagrams/Chevy%20Corvette%201965.pdf

The confusion about Blk/Wht is that earlier cars used Blk/Wht as a ground. In later years it was typically not a ground.

Rich