[Mk2] [Turbo] Horn issue

[DaveWS]

I've been tearing my hair out over this, I can't get it through the MOT because of it, so I'm all ears to a bodge fix.

Horn hasn't worked for a while now. Put through MOT and all is well, just need this sorted to get a pass (only got a day left though before 10 days is up).

Relay makes a tick noise when I press the button, so that seems fine. I exposed the green / white wire that runs to both the horns from the fuse box and connected up a multimeter to that and earth - it shows 12v on the meter when I press the button. I've got an aftermarket horn to mess about with and potentially use temporarily, but when I put it in place of the meter, I get nothing! The horn works if I connect directly to the battery.

As a last resort I've tried connecting the horn directly in place of the relay (tested first to ensure I've got terminals correct) and when I press the button this time the horn jumps very briefly without making a horn sound...

Any help would be greatly appreciated, I'm pretty desperate at this point!

[Pauln]

Ok, yes the click seems to suggest the relay is pulling in, but what voltage is being sent to the horn.

I'd start by measuring the voltage between relay terminal three and the chassis when you press the horn button. If you have 12v or so then the relay is fine. If the voltage is low it's probably corrosion of the relay contacts. If the relay can be take apart you can try cleaning the contacts up, or failing that fit a replacement relay.

If the relay is OK, then it's most likely that the horn isn't earthing where it's fixed to the chassis due to corrosion. If it's not that, the only thing left is a damaged wire from the relay to the horn. Just run a new wire in.

But unless you've already checked, my money would be on corrosion where the horn bolts to the chassis.

Paul

[DaveWS]

Thanks Paul, the multimeter says 12volts and reads the same as when I touch directly to the battery. I've also tried an aftermarket horn, grounded separately etc and still no joy.

It's going in the garage for now, I've lost patience!

[shinny]

Have you tested the ground wire on the horn?