GaryBZ Posted March 21, 2022 Report Share Posted March 21, 2022 There are a lot of posts about horns that don’t work. I have read quite a few, but still haven’t found an answer to my problem. I have checked the function of the horns by connecting 12v directly to the horns and they work fine. The in-line fuse is fine. I did find a bad earth connection across the upper steering column doughnut, which is now fixed. I have connected a 12v supply to the purple/black wire at the fuse, assuming that this should power the relay and sound the horn. It doesn’t and there is no click from the relay. I checked the voltage at the horn push and it’s only 5v. I came directly from the horn slip ring to a good known earth and it’s still only 5v. I’m guessing that the relay may be faulty and I have a power supply problem. Before I start buying parts and stripping things down, does anyone have an idea what may be going wrong. Gary Quote Link to post Share on other sites
GaryBZ Posted March 21, 2022 Author Report Share Posted March 21, 2022 I think I have this wrong, don’t I? The horn push just makes the circuit when it is depressed. Attaching 12v to the fuse wire won’t do anything without the horn push working. I guess I need to work back from the horn push? Gary Quote Link to post Share on other sites
RobH Posted March 21, 2022 Report Share Posted March 21, 2022 (edited) The voltage measured at the horn-push will be lower than 12v because the current is flowing through the relay coil. You can check the operation of the relay by earthing the W1 terminal. (connecting 12v to that wire will do nothing as the relay then has supply on both sides of its coil.) The usual cause if the relay is OK is a poor earth connection via the horn push. Edited March 21, 2022 by RobH Quote Link to post Share on other sites
RogerH Posted March 21, 2022 Report Share Posted March 21, 2022 Hi Gary, as per Rob's diagram, connect a fly lead to the relay W1 spade fitting. Touch the other end to the battery -Ve post. If it works then transfer to the steering column - start with the upper joint as it is easiest to get at If it works move to the brass ring on the steering wheel. Does the spring contact in the steering function correctly? Roger Quote Link to post Share on other sites
GaryBZ Posted March 23, 2022 Author Report Share Posted March 23, 2022 Thanks, Roger. Done all that. The horns work. There is power where it should be. If I bypass the relay and press the horn push they work. Ordered a new relay from Holden. Gary Quote Link to post Share on other sites
GaryBZ Posted March 25, 2022 Author Report Share Posted March 25, 2022 Chaps, Scratching my head now. I bought a new relay from Holden. This has an extra terminal W2, which I am told is an earth. I checked to see if it is connected to the body of the relay and it is, so I have left it alone. I fully expected the horns to work with the new relay and they don’t. As you have suggested, I have connected and earth wire directly to W1 terminal and nothing happens. I have 12v at C1 and there is a good earth at the relay and the horns. If I connect 12v to one of the horns it works. Could it be that I have two faulty relays, or should I look elsewhere first? Gary Quote Link to post Share on other sites
GaryBZ Posted March 25, 2022 Author Report Share Posted March 25, 2022 Sorry, should have said 12v at C2 Quote Link to post Share on other sites
RobH Posted March 25, 2022 Report Share Posted March 25, 2022 (edited) Your original relay has W2 and C2 linked inside the relay, so the only input terminal provided is C2. For your new relay you need to make that link externally, i.e. 12v has to go to both C2 and W2. If your new relay is a Holden SRB111, W2 is not connected to the relay can. I suspect you made that measurement without first removing the connection from W1. If there really is such a connection, the relay is faulty. Edited March 25, 2022 by RobH Quote Link to post Share on other sites
GaryBZ Posted March 25, 2022 Author Report Share Posted March 25, 2022 I did try the connection without removing the W1. Chap at Holden told me it was an earth. Great, I’m going out now but will try what you have suggested tomorrow. Many thanks Gary Quote Link to post Share on other sites
GaryBZ Posted March 26, 2022 Author Report Share Posted March 26, 2022 Rob, Hats off to you. Connected C2 and W2 as you suggested and Bingo, it works fine. Given the information I was given when I bought the new relay I would have never of thought to make that alteration. Thanks to you and Roger for helping me with this issue. It’s very much appreciated. I am now only waiting for a none damped crank pulley and I can set up the electric fan, alternator and narrow belt system. Gary Quote Link to post Share on other sites
johnwill Posted March 28, 2022 Report Share Posted March 28, 2022 Late to this, and glad you got it resolved. I had a slightly different issue couple of weeks ago. I have my electric fan powered from the horn relay. my 4A boiled over (en route to Dave Gleeds funeral of all times to happen) At home, I checked it out, and for once used the “start with the obvious” method, and checked the horn first. It didn’t work ! turned out the inline fuse was fine, but the springy thing in the fuse holder had come apart at one end. Touch the fuse holder slightly, and it all worked, let go, and it stopped again. Replaced the inline fuse holder and all was fine. John (did get to the funeral service in time after letting it cool for a few mins) Quote Link to post Share on other sites
GaryBZ Posted April 7, 2022 Author Report Share Posted April 7, 2022 John, even though I fitted the new relay, with the modification suggested by Rob, I still had an earth problem with the doughnuts. I solved that in the end by putting new earth straps on both doughnuts. I used the spline clamping bolts for better connection. It worked fine. Gary Quote Link to post Share on other sites
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