Horn electrickery

[theelanman]

Blooming typical........
MOT day omorrow and my horn has packed up...... I am awful with electrics....... anybody got any good suggestions?......... my MOT is booked in for 12noon..... so I have the morning to play with the car
Do we think, for an electrical idiot, that will be enough time
I suppose I need to invest in some metres/gauges/testing equipment etc
Any help/guidance/information would be much appreciated
thanks
Gareth

[jimj]

Gareth, it could be as simple as your horn button, the whole thing, rotating slightly so that the metal strip is not aligned with the sprung " pencil". If not try a piece of wire touching the pencil and the steering boss (to earth) and see if it beeps, with the ignition on. If not you need a bulb attached to see if it lights, if so, do the same thing, horn to earth, to see if power is getting there, if not is your column earth strap damaged? You`ll soon see if it`s the button or the horn. I bet it`s just the connection from the "pencil" to the button.
If you`re still struggling, I`m at home tomorrow a,m. with wire, bulb and coffee.
Jim

[billwill]

Not really practical to give you a whole school electricity course in one evening..

First test the horn itself, for this you need a spare car battery, or take your out or use long wires from the boot.

Pull off the connections from the horn and then using two wires from the battery (taking care that the ends don't touch each other) connect to one terminal and briefly touch the other wire to the other terminal, also try with the wires reversed.

If it doesn't sound, the horn is faulty. Quickest fix is to fit one that already works, buy a new one or borrow off another car.

Then fix the faulty one at your leisure.

If it is an air horn the motor has probably seized, lubricate & turn by hand until it is free, reassemble and test again.

If it is a buzzer type horn the buzz contacts are probably corroded, try screwing the adjuster down & up while trying the 12 volt electricity (on a bench) to see if you can get a sound from it.

~~~~~~~~~~~~~~

Or the simple but more expensive approach, ask the MOT test garage to fix the horn before the test.

[john.p.clegg]

Gareth
I have my haircut booked for 10:30 but if you have the kettle on early I'll come and sort it for you...

John

[AHM]

The horn has switched ground so has power at the horn with the ignition on.

First check the fuse

Test
1 with a Meter or bulb between the power terminal on the horn and earth.
If ok
2 using a piece of wire touch one end on the ground terminal on the horn and the other to chassis earth. Make sure you have the correct terminal as the wrong one is a short! Which will blow the fuse.
The horn should sound
If ok
3 Remove the horn push - one end of the piece of wire onto the end of the pencil and push down, then touch the other end onto the nut in the middle of the wheel
Horn should sound
4 check the wire link across the column uj
5 check the earth wire from the rack to chassis

Simple as that

Hope you find the fault!

[theelanman]

All good thanks......
My centre horn push was taken out years ago so my horn was on the stalk........
I'm thinking it could be time to resurrect the centre button.......

John......are you serious?.......where are you getting your hair cut......lol......
I'm a long way away ..........

Thanks chaps......

[Europatc]

John P top man

[theelanman]

Thanks for all the help chaps
I managed to get it sorted
there with power to the original compressor but the compressor just didn't fire up so as an interim I just screwed an electronic buzzer type in its place..... this was enough to satisfy the MOT station and all is well
I will endeavour to put a half decent compressor back in, in the next couple of weeks and connect up as it was
thanks again for all your help and advice
absolutely priceless
cheers
Gareth

[billwill]

As I said above air horn compressor motors often stick (as we don't use horns much nowadays). They just need oiling and freeing up.

I wired a buzzer horn in parallel with my air horn so that in-town a quick tap on the horn button give a pedestrian-warning beep and a long press in the country (on a motorway) sounds the air horns. You can't hear the buzzer when the air horns are sounding

[pereirac]

My air horns were originally wired directly through the steering column and while they worked, they were a bit pathetic. Adding a relay into the circuit, not only meant the steering column didn't have to pass such a large current but also improved the sound as the compressor could be driven straight from a 12v supply. It was a very easy upgrade.

Carl

[RichC]

that reminds me of my trip to the mot station in december after long rebuild !....... car's already been gone-over thoroughly several times .....so EVERTHING works. Nice new set of twin tone hella horns
I was actually driving there in a hurry - its 15 minutes max , and i pipped the stalk a few times whilst driving, i don't know what possessed me to do it as EVERYTHING works,.... but there was no horn sound .... and then a few times more i pipped it but harder , but to my utter horror there was still no sound ... my mood darkened and I felt the +2 was acting very ungraciously considering all the love and attention it had been receiving of late..... I became resigned to the inevitable MOT failure.
I drew in to the garage & showed the chap the ropes, where to find handbrake, security device etc and the horn on the stalk , here! PARP PARP !... it worked !
I do try it every now and then and it's fine ...moral of story ... watch ' 80s film 'Christine' and you become grateful for small mercies

[pereirac]

I wonder where you stand MOT wise with a hand held air horn on the passenger seat?

[richardcox_lotus]

I know someone who carried a vintage car horn on one MOT and it passed....it fulfilled the need !

Regards,
Richard