TR4 AJJ Posted August 31, 2019 Report Share Posted August 31, 2019 Hi all, TR4A with twin horns. They just make a clicking noise when the horn is pushed. So, I can assume the relay is working (it’s not the relay that’s clicking). If I push the horn I can feel the horn solenoid clicking in but nothing else. I took one apart but there doesn’t seem to be much in there. I couldn’t work out how they actually work. They appear to be quite new ( I’ve had the car 18 months). Any advice ? Is this common. I guess I hardly ever use them Thanks in advance Andy Quote Link to post Share on other sites
RogerH Posted August 31, 2019 Report Share Posted August 31, 2019 Hi Andy, using a length of decent wire connect the battery to the horn direct. if this doesn't work check the continuity between the horn body and the battery -ve pole. If this is 0 ohms then horns could be dead (but two dead horns is improbable Roger Quote Link to post Share on other sites
RobH Posted August 31, 2019 Report Share Posted August 31, 2019 It depends on what you have since you say they look new, but horns usually work by having a thin metal diaphragm attracted by an electro-magnet. The movement of the diaphragm opens an electrical contact which interrupts the coil current so the diaphragm drops back again whereupon the contact is re-made and the cycle repeats hundreds of times a second. As you say, there's not much to see in the mechanism. The clearances are small and it doesn't take a lot of crud or mal-adjustment to stop it all working. If you just hear a click it may be the diaphragm is moving once but the contact is not being broken so it does not cycle. Depending on the type there may be an adjuster screw which allows the clearances to be set and which will also change the note bit. This video is for adjustment of Lucas wind-tone horns. Quote Link to post Share on other sites
TR4 AJJ Posted August 31, 2019 Author Report Share Posted August 31, 2019 Thanks Roger. Thanks Rob, that is an excellent description and basically what I have going on. They are both plastic bodies, so a lot newer than the one on the video. Inside there is a small contact and a solenoid. Looks like I need to do a bit of contact cleaning and look for any adjustment, etc. Cheers Quote Link to post Share on other sites
ctc77965o Posted August 31, 2019 Report Share Posted August 31, 2019 before you take them apart, whack them with a heavy piece of wood whilst energised...thats often enough to make the contacts inside to connect and after beeping for a while theyll clean up and work long-term if used regularly.. Quote Link to post Share on other sites
ChrisR-4A Posted August 31, 2019 Report Share Posted August 31, 2019 Is the fuse passing 12v, they grow green fungus over time, I check mine once a year now as I've been caught out a couple of times. Chris Quote Link to post Share on other sites
TR4 AJJ Posted August 31, 2019 Author Report Share Posted August 31, 2019 50 minutes ago, ctc77965o said: before you take them apart, whack them with a heavy piece of wood whilst energised...thats often enough to make the contacts inside to connect and after beeping for a while theyll clean up and work long-term if used regularly.. Thanks I will ... although I might give them a clean up anyway and a spray of WD40 Quote Link to post Share on other sites
TR4 AJJ Posted August 31, 2019 Author Report Share Posted August 31, 2019 48 minutes ago, ChrisR-4A said: Is the fuse passing 12v, they grow green fungus over time, I check mine once a year now as I've been caught out a couple of times. Chris Thanks Chris, i have a completely new blade fuse box, with about 20 fuses in it. They are in excellent condition so they're unlikely to be my issue. I think it’s the internal contact that needs a clean .... or a whack ! Quote Link to post Share on other sites
stillp Posted August 31, 2019 Report Share Posted August 31, 2019 Is the earth connection OK? I'd try them straight across the battery before whacking them. Pete Quote Link to post Share on other sites
ed_h Posted August 31, 2019 Report Share Posted August 31, 2019 Since your horns are apparently not original, this may be of limited help, but most horns work on the same principles. http://bullfire.net/TR6/TR6-69/TR6-69.html Quote Link to post Share on other sites
TR4 AJJ Posted August 31, 2019 Author Report Share Posted August 31, 2019 1 hour ago, stillp said: Is the earth connection OK? I'd try them straight across the battery before whacking them. Pete Yep, first thing I checked but thanks Quote Link to post Share on other sites
TR4 AJJ Posted August 31, 2019 Author Report Share Posted August 31, 2019 1 hour ago, ed_h said: Since your horns are apparently not original, this may be of limited help, but most horns work on the same principles. http://bullfire.net/TR6/TR6-69/TR6-69.html Thanks Quote Link to post Share on other sites
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