Horn earth ... where to attach wire?

Firstly, please don’t take the proverbial. I’m a complete numpty so bear with me…

Trying to get non-operative horn to work for MoT on Monday. So. Took horn push button out of steering wheel. Found loose wire, since figured this out to be the earth.

Fiddled about, wondering if fuse and/or relay were gone. Brake lights work so fuse OK. With ignition on but engine not running I speculatively pressed button while touching wire to various bits of steering wheel boss. I could hear the relay clicking. So that was good. Checked under bonnet and slip-on wire to one of the horns was adrift. Reconnected, taking most of skin of left hand in process. Back in, ignition on, repeat, touched earth wire to inside of hole from whence the horn button came and fuse went pop. No toot. No brake lights. I put another fuse in, brake lights working again, tried holding wire against inside rim of the hole and the same happened.

I’ll go out and get some more fuses but where should the earth wire from the horn switch be going? Am guessing not floating about in the steering wheel boss!

Like I say, forgive me because I really don’t know diddley squat. But I’d appreciate any tips as to what to do with this errant earth before I start going through fuses again. Trial and error has got me this far but there’s been a bit too much of the latter and I need help!




edited for numptyness and not reading properly

Ah… It’s got an earth symbol on the terminal from where it’s coming on the horn switch and I can’t see any obvious signs of another end of a wire in the steering wheel boss. I took the wheel off and the shroud around the binnacle and no other half to the blue wire.

Ho hum. I was thinking this was going to be about the simplest thing known to man but it looks like I’ll be adding it to the to-do list for the MoT boys!

Impressive rapid response though! Thanks!



I’ve just had as quick look at my horn push (nothing better to do on a Saturday night - sad I know).

There’s only one connection, the earth is picked up by a spring acting against the metal of the steering wheel. Perhaps your blue wire had just been trapped between the push and the wheel to pick up the earth? That might explain the exposed cable end…




Glad I’m not the only one! “I’m just going to put the rubbish out…”

“On a Saturday? With a head torch? And a Haynes manual?”


I know this sounds a bit takey the piissey, but it should go to ground! Does the horn push work if you temporarily ground it against something metal and connected to the car?

It looks to me like someone has already had to bodge it. A better (quicker) bodge would be to rig up another temporary button, write ‘HORN’ on it, and point your MoT tester at that. Then fix the problem when  there’s less pressure and you can find someone to help.

No, that’s absolutely the level of explanation I need so thanks!

Have got a handful of fuses, will go and have a fiddle. And if that doesn’t work I’ll leave it to the boys at the shop knowing that I at least had a go! Frustrates me that something so trivial might fail it, more so that I haven’t been able to sort it but such is the way of it. Thanks for the tips though, much appreciated.

Happy new year, Dan… high time we met up for a drink. The horn itself is earthed to the car body, which is why there’s only one (live but switched) wire to it. Which means the horn switch doesn’t have an earth connection. It must have a live in and switched live out, which is why a fuse blows when you earth it.

I hope that helps, in theory anyway.