S2 horn wiring.

[MartinBrown2409]

Hi all, I have managed to get all electrics working so far on my 1990 S2 apart from the horn. Haven’t managed to look under any other S bonnet so hoping someone here can help me with wiring tips as I haven’t been able to find any info as such. Have twin horns but no wires going to one of them at all. Have a purple wire that is really stretched to connect to one horn, in this “loom” there is a black earth connected to the chassis.
From another loom I have a black wire connected to the same horn and a two purple wires going into same connector not connected to anything.
Have tried a few different combinations but not getting anywhere. It isn’t the fuse, hopefully someone has similar setup and can tell me which goes where.
Thanks

[phillpot]

Do you have...........

a. a wiring diagram?

B. a test lamp or meter?


Feed to horns should be purple with a black trace, this should become live when horn push is pushed. This wire may split somewhere to feed both horns or it may "piggyback from one horn to the other.
If no live then try fuse (there have been a few fuse box layouts, sure you're checking the right one?) if fuses all okay you've got a bigger problem!

both horns will require an earth from their other connection to, you've guessed, earth. If the earths are good trying using a spare length of wire and holding on battery +ve and touch horn terminal...... any noise?


There may, or may not, be a relay in the circuit? Wiring diagrams in Steve Heath book show a relay on the V8s (think my S3 has one but too cold to go out and look) but S3/V8s fuse and relay layout doesn't show a relay???

Edited by phillpot on Monday 7th January 20:51

[MartinBrown2409]

Thanks I will give that a try, I believe that the same fuse does the clock as well and that’s now working. Yes the purple wires do have a black trace. So I have twin purple and a single purple and two earths so looks like maybe the earths aren’t good enough.

[Steve_D]

Back to basics start by taking live & earth wires direct from the battery and prove each horn actually works. Then connect the earth wires from the loom to each horn and prove those with the battery live.
Then all you need to do is find some +12v for the purple/blacks. Simples.

Steve

[RayTVR]

Sorry if this is completely obvious, but...

You do know the horn push is on the end of the left hand stalk and not the centre of the wheel?

[MartinBrown2409]

Hi Ray, lol.. yes mate. But you never know....

[MartinBrown2409]

Hi all, thanks for advice, complete novice when it comes to car electrics. Horn now working, poor earths.

[greymrj]

good to know you have sorted it. Just one extra thought for the future. You may find that the wiring for the horn comes forward from the passenger side, crosses across the front and loops back to the passengers side horn then parallels to the drivers side. A lot of wasted wiring and potential problems! If you ever start tidying the front harness (sounds like you may need to as there can be quite a few corroded joints etc|) then find the purple/black on the passengers side and connect direct to the passengers side horn and loop on directly to the drivers side horn, and shorten the earth wiring in the same way. Couple of meters of wiring junk removed!
The S can also suffer from insufficient earth capacity to the front lights, which puts too much strain on the existing earthing connections. I have run a new, heavier duty, earth to the chassis under the swirl pot.