Horn not working. MOT retest due monday!!

The horns weren't working so I used a power probe to test the horns and they were faulty.

I thus replaced both horns and they both work using the same test.

There is a 12v voltage at the positive terminal and if I earth either horn they sound.

When I pressed the horn button I could hear the relay click, but this no longer happens.

Anyway I could just link the horn button to the actual horns? Or must I use the relay/fuse box??

If so what terminals should be going where??

Cheers in advance

The horns are supplied with a permant 12v + supply via a fuze and relay in the fuze box . Firstly if you cant hear the realy the fuze may be blown [10 amp] or the relay is faulty [haynes for exact location]. If thats okay then the earth supply from the steering colum may be the next port of call , set up a test bulb or use a didgi meter on ohms [tone] and put one wire to the earth on the horns and the other to the earth [brown] in the steering wheel . Push the horn and you should have a continuous curcuit .

This will tell you what parts faulty  !  You could also try just one horn , disconnect one only then try , it may be the wiring is old and will not support both horns , if so just use one . Or build a relay near the horns .

Hope this may help ?

Chudd………

what wires go where on the terminals of the relay though???

is the steering rack earthed? it must be for the horns to work, it is normally drivers side front of the rack earthed to the chassic by a short wire.
hope this helps.

yea check the steering column earth. Unfortunately its undernearth the car outside. You could check continuity with a meter from the horn pad in the steering wheel before you go groveling around on the floor.

On my GTI I found the horns to be very problematic and currently it seems to work if just ones connected. Got another winging its way to me via ebay so I will try and get both hi and low tones to work next week.

when i earth the steering column direct using a power probe the horn still doesn't operate.

I need to know what terminal are for what on the relay, then I can check for continuity between what should be connected.

i've swapped the relay with a known good one from my golf and there is still no clicking.

cheers

Just carried out a few tests and this is what I found:

Fuse Intact

Connection between horn press and terminal 85 are fine.

Ignition Off
85-blue/brown no charge
86-black         no charge
87-brown        negative
30-brown        negative

Ignition On
85-blue/brown  no charge
86-black           no charge
87-brown         positive
30-brown         negative

Ignition On and Horn Pressed
85-blue/brown   negative
86-black            negative
87-brown          positive
30-brown          negative

There is a 12.5v at the positive terminal of the horn, the horns are new and function properly when using a power probe.

The thing is when I press the horn press, nothing happens!! no relay click, no output.

However if I use my power probe and apply a positive voltage at terminal 86-black and then operate the horn press the horn sounds.

Can someone figure out what is wrong here?? I would have thought that the black would have had a positive rather than 87-brown???

I need to sort this by monday.

Cheers

currently it seems to work if just ones connected.

Same as me ……..The relay is too far away from the horns because the old cable is suffereing fron poor conductivity [inner black death] and voltage drop . If you were to move a relay next too the horns and use battery poz direct as a power supply the problem would be cured .

Getting back to Gareth …….You should have continuos power at term 30 fuzed to the box . You should have live at 87 when the relay is earthed ….And this earth comes via the steering collum so it must be the earth missing from somewhere .  :dontknow: Are you sure you have a continous cable from the horns push to the horns them selves , and remember this is the earth needed to activate the relay , push the horn push , complete the curcuit relay clicks in horns work .

Cheers …….

Is the horn wiring the same for the driver as the gti- 12v permanent feed etc?   As i'm trying to fit a new twin air horn, and all i'm getting is the buzzing of the compressor , so i cant tell whether its the wiring or the horn.

(Sorry for hijacking ops: )

Cheers,
Arun

what wires go where on the terminals of the relay though???

Unless some one has messed with the fuze board the relay only fits one way


Normal relay is 87 power to equipment . 30 live poz feed fuzed . 86 switched live feed [on off switch] . 85 earth .

Arun

You need to do this

…………The relay is too far away from the horns because the old cable is suffereing fron poor conductivity [inner black death] and voltage drop. If you were to move a relay next too the horns and use battery poz direct as a power supply the problem would be cured ………


The buzzing is because you don't have enough zap to run the compressor .
If you have followed the 'Dim lights' on a mk1 saga you will follow what i mean . Fitting a relay for you is the only way .

Cheers………

so from looking at it, how should i adjust the wiring???

just swap 30 and 86 round???

Take an old vintage car hooter.. Clip it to the open driovers window..

It should pass the MOT then.

TT