barrymknight Posted August 25, 2011 Share Posted August 25, 2011 Hi all,My MKIV Spitfire developed an odd problem last night. When I turn the steering wheel more than about half a turn the horn sounds!Any ideas what may be causing this?Thanks,Barry Link to comment Share on other sites More sharing options...
heraldcoupe Posted August 25, 2011 Share Posted August 25, 2011 Is it an aftermarket steering wheel?Cheers,Bill. Link to comment Share on other sites More sharing options...
barrymknight Posted August 25, 2011 Author Share Posted August 25, 2011 Sorry, all I can tell you about the steering wheel is that it was on the car when I got it!I have found that it only beeps when I turn right. I have disconected the horn for now but with it disconnected I get a loud clicking noise when I turn the wheel right. It seems to be comming from the dash somewhere?!It may be coincidence but I had the RAC out yesterday when it wouldn't start. He spent time messing with the coil (although it had nothing to do with the coil, it was the choke stuck wide open).Barry Link to comment Share on other sites More sharing options...
smithy Posted August 25, 2011 Share Posted August 25, 2011 I suspect the copper track your horn pencil runs around might be a bit corroded. Take the steering wheel off and have a look, maybe clean things up. ;)Even with the horn disconnected your horn relay's clicking away trying to do its job.... Link to comment Share on other sites More sharing options...
heraldcoupe Posted August 25, 2011 Share Posted August 25, 2011 The metal rim of the steering wheel can make contact with the contact ring in the steering column, completing the circuit. Aftermarket wheels often run very close to the ring, look also for telltale signs of worn aluminium around the top of the column, where the wheel boss is grinding against the column outer.This can happen with original wheels too, invariably when the top bush in the steering column is worn. Check for play, but also look for a manufacturers name on the steering wheel. Cheers,Bill. Link to comment Share on other sites More sharing options...
phards Posted August 25, 2011 Share Posted August 25, 2011 On mine the ring turned, pulling the wire so that strands from the wire could cause an earth.I tried to fix it ... several times, but now have given up and just added another switch. (It would be fine, then randomly just start hooting at a roundabout)good luck!Paul. Link to comment Share on other sites More sharing options...
smithy Posted August 25, 2011 Share Posted August 25, 2011 Bills descriptions far better than mine of course - getting a bit old and absent! Mine was an original wheel at the time, and rubbish.Moons ago I also remember getting the thing through an MOT turning the wheel a bit to get it to work while the tester wasn't looking. Happy days.... Link to comment Share on other sites More sharing options...
Howard81 Posted August 26, 2011 Share Posted August 26, 2011 Mind used to do this but I adjusted the column out about an inch which cured it.. Link to comment Share on other sites More sharing options...
junkuser Posted August 26, 2011 Share Posted August 26, 2011 Maybe worth adjusting the sliding joint in the steering column to move the steering wheel up a millimeter or two in case the hub is contacting the surround.If you put the wheel in the positing where the horn gets excited, then pulling the wheel up, may tell you if this is the possible cause.This can be the problem in Mk.1s but I'm not familiar with your model. Link to comment Share on other sites More sharing options...
barrymknight Posted August 30, 2011 Author Share Posted August 30, 2011 Thanks for all the replies. Planned on looking at this at the weekend, reconnected the horn and now it doesn't work. The horn is completely dead!What's going on!Barry Link to comment Share on other sites More sharing options...
barrymknight Posted August 30, 2011 Author Share Posted August 30, 2011 Just been checking the obvious things and the bottom fuse had blown. Replaced this and still no horn!Barry Link to comment Share on other sites More sharing options...
heraldcoupe Posted August 30, 2011 Share Posted August 30, 2011 You need to wave a multimeter at it and see where you've got volts!Seriously, there's no simple "it will be this" answer, this may or may not be related to your original fault. Fixing it by guesswork is a pretty frustrating process, a simple meter will quickly show you where the circuit is broken,Cheers,Bill. Link to comment Share on other sites More sharing options...
barrymknight Posted August 31, 2011 Author Share Posted August 31, 2011 Thanks again chaps.It now looks like I have more than one problem (all linked though).This is going to sound long winded but here goes....The horn suddenly started sounding when turning right. Disconnected horn until I could look at it. Whilst discounted, I could still hear the horn relay clicking when turning right.Reconnected the horn. The fuse blew. Changed the fuse. Horn dead. Relay still clicking when turning right but not when pressing the horn!I'm very much an amateur learning as I go so not sure if the next thing was the correct way to check but....checked the voltage at the relay with a multimetre. Fine, approx 12V. Checked at horns. Nothing at all.I could still hear the relay clicking when turning (but no horn, even when connected). Took the casing off of the steering column to investigate why the relay was clicking pretty much whenever I moved the wheel now. Now what I found, I'm certain isn't right, though I'm not sure what it should be like.Inside, there was a completely seperate piece of purple wire, not connected to anything, about 3 inches long, just laying in there?! Really odd! secondly, I found another purple wire (this one was the live one and came from a bullett connector). The other end, at the back of the steering wheel, was not connected to anything, with bare wire at the end.In addition, there was a single strand of copper (I thik) wire wound around the steering column, fixed behind the horn push but lose at the other end. It seems that when the wheel was turned, this single strand would touch the bare end of the purple wire (occasionally and randomly) and make the connection which made the relay click. However, the horn push had no effect at all. Really sorry for so a long post. Anyone who read this far, congratulations and thank you! I really do not know how the wire behind the horn push should work but I'm certain that this isn't right, nor the sparks when the wires touch!Any advice on what to next would be appreciated.Many thanks,Barry Link to comment Share on other sites More sharing options...
heraldcoupe Posted August 31, 2011 Share Posted August 31, 2011 Like so many faults, it looks like this is down to a previous owner's 'improvements'.The single strand of wire around the column shouldn't be there. According to the MkIV diagram in the Haynes manual, you should have a purple/black wire from the brass horn contact ring, which leads to the relay. The other side of the relay should go to the feed from the fusebox. When the hornpush is pressed, the purple/black wire is grounded, so activating the relay which switches the live feed to the horns.For the hornpush to ground the purple/black wire, the column itself must be tied to ground. The steering rack is grounded by a cable from the greasing point to the rack clamp. There is a further link inside the steering joint between column and rack. The original joint's link is internal and can only be observed by dismantling the joint. The link is fragile, and is frequently replaced by a cable link between the joint's pinchbolts.Hopefully that helps and at least explains how the circuit should work.Cheers,Bill. Link to comment Share on other sites More sharing options...
Howard81 Posted August 31, 2011 Share Posted August 31, 2011 If you remove the steering wheel there should be a copper ring on the end of the column. A purple wire is attached to this which goes down the column where there is a bullet connector that goes into the loom.With the steering wheel on there is a little pencil type thing that goes through with a spring in it that contacts from the copper ring to the horn button. The horn button clips on, a metal spring bar contacts the wheel centre earth and the metal tab on the back touches the pencil.Make sure that is all in place and correct!I had similar problems with my car. The purple wire was dodgy, the horn pencil had been replaced with a bent nail and the (brand new) horn button was falling apart! Link to comment Share on other sites More sharing options...
barrymknight Posted September 2, 2011 Author Share Posted September 2, 2011 Thanks again chaps. That makes it very clear and now seems obvious, as Bill said, a previous owners botch job has finally failed!Now I understand how it 'should look', the problem must simply be the break in the purple wire.I have ordered a new slip ring (excellent price/service/delivery from James Paddock) which should hopefully sort it out.Thanks again,Barry Link to comment Share on other sites More sharing options...
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