Horn issues - pressing horn = horn + wipers!

[PabloGee]

Posted same thing on a different thread - Steve D very helpfully sent me (and many others) his wiring diagrams of the Chim/Griff.
PM me (or him) for the pdf that's nice and clear to see - here's one of the pages in case it's useful.
edit - the resolution is terrible on the image upload feature here, you'll need the pdf to read it.

It echoes the manual diagram - that the horn and wipers should be on different relays

[Mark-ixql7]

Only just got around to looking at this now the weather is improving. I've taken the radiator out to replace with a new one whilst I'm at it. So, it seems to be the drivers side earth from that horn is faulty. After cleaning up the front earth point...

Plugging either horn in to the passenger side and leaving the drivers side unplugged - both horns are working and the wipers don't go.

Plugging either horn in to the drivers side and leaving the passenger side unplugged, horn doesn't sound but the wipers go.

I get no continuity from the drivers side earth lead at the horn. It looks like it's a very short run from there to the front earth point? I'm guessing it must be a break in the wire and the correct thing to do is unwrap it all to try and find it incase there are more breaks... Though it's very tempting to just run a new wire for the horn and call it a day!

[Belle427]

If its only a short length you have to unwrap then do that, try to keep it as oem as you can but do it better!
I would have considered moving all those grounds to a more accessible location in the engine bay if i had the radiator out, not sure how tricky this would have been as i never did it.

[Mark-ixql7]

Ok, so the break was about 1cm from the chassis mount. I noticed tape had rubbed through. After peeling it back a bit the break was clearly visible. Managed to solder the break back together, tape it back up and the horn now works again!

[PabloGee]

Glad to hear your fixed it, Might be worth considering either heat shrink (though may not be possible to put on now you've soldered it up) or liquid wire insulation rather than tape, especially in that location.

[Mark-ixql7]

Yeah, I used electrical tape and then decided to go over it with some self amalgamating tape. Hopefully that'll help keep it from rubbing through again!