My 67S had a horn problem as well. I found the tiny block that rides on the collar was just dirty as all get out. I sprayed it, then ran a super fine sandpaper between the two. Good as new. (which isn't really that good).

I'd try that.

Sorry Doug

Never did get back to you and thank you for the direction to the other thread. It helped!!!!! Been installing a 1293 all year and just have to fine tune the Weber. Just hooking up all the gauges when I popped over this thread again looking for another wire color. Found it too!!

Cheers Todd

Before you get too complicated, remove the streering column shroud and check that the shiny gold bits (you'll know 'em when you see 'em) that connect the steering wheel to earth are actually touching each other.

Cheers, Ian

Todd, see the picture and discussion in the link below.
//www.theminiforum.co.uk/forums/index.php?showtopic=148242&hl=horn

Let us know if it helps.

 

Good Day Folks

On the topic of horns, one of the previous owners broke the wire leading to the center button. Can this be replaced. Where does that originate to get through the center of the steering column? What is involved to put in a new wire. Again 1967 Mini MK1. Currently I have air horns with a make shift button on the steering shroud. Just an eye sore I want to fix. : )

Cheers Todd

With out a doubt, a relay is the way to go.  I wired every circut on my car with relays. Being that it is an original S, I would think that a relay would upset the purist. I would say that if the horn worked good from new, it can be made to work as new again. The problem will be to find and correct the fault.

Both JayA1010 and Larry are right.  You can follow the troubleshooting steps listed above and you may find the problem.  However, with my car, even with a new wiring harness and cleaned horn contacts, my car's horn would only weakly groan, not honk.  I added a horn relay to the circuit so the horn push-button only needed to energize the relay.  The horn works MUCH better this way.  FWIW, later British cars included a horn relay.

The horn circuit has too much resistance and therefore there is not enough voltage to hoot the horn. This is typical of aging electrical wiring and and aging horn. The easy solution is to add a relay, powered directly from the battery with a wire form the starter solenoid and have it operated by the horn circuit ie the purple and purple/black wires now attached to the horn.

The horn should have a "hot" wire,  purple, from the fuse block to the horn. the other wire on the horn is purple/black. It goes to the steering colum,to the horn push and then back to ground. So when you push the horn button you complete the ground circut to the horn. Look at the conector at the middle of the steering colum and find the purple/black wire.  With your volt meter test for voltage at the purple and black wire. you should find about 12 volts. ( the eletricity is trying to make a complete circut , through the horn, but can not untill you push the horn button). If you have 12V at the puple/black wire try grounding the wire and see if the horn blows. If so then the horn button or the contact or the colum are bad.( I would guess that the contact is bad.) also the black wire at the steering colum conector needs to have a GOOD conection to ground. 

To get it past inspection, why not just wire the horn direct to a push-button switch that you could mount on the column?  That would give you time to suss it out while you drive the car...

Can't pass inspection with no horn.  I put my meter on the two leads attached to the horn...nothing when I push on the horn stalk.  Took the horn out, hooked it up to 12V, works fine.  Any fixes out there for the horn switch?  Am I stuck buying a new unit?