There isn't really a good time to find out that your car's horn isn't working, but there are plenty of very bad ones.
Like many cars, the Vauxhall Corsa uses an electromagnetic snail horn, positioned inside the front bumper. Although not directly in the path of road grime, they do tend to get a bit wet and eventually end up knackered.
Although located behind it, it is possible to replace the horn without needing to remove the bumper.
This post details how to replace the horn on a Vauxhall Corsa Mk5 (2015 onwards) - I'm fitting a generic horn, but the process is the same if you've bought one from Vauxhall.
Things to check first
There are a number of reasons that your horn might not be working, so check the simple stuff first.
Check the interior fuse-box (behind the panel in the glovebox, or for lefthand drive, under the switches to the side of the steering wheel), there may or may not be a fuse in position 24
If there is a fuse there, check whether it's blown.
Secondly, check the exterior fusebox - this is under the bonnet to the right of the battery. The fuse is at the very bottom, on the left of the central set:
Check whether this is blown.
Once you've checked the fuse isn't blown, have someone press the horn whilst you listen by the fusebox
Does the horn relay click?
- Yes: the issue is likely the horn
- No: the issue is more likely to be the relay or (nighmare scenario) the horn switch in the steering wheel)
If you want to doubly confirm whether it is the horn and feel confident doing so: put a multimeter between the battery's positive (use the jump connector) and the horn fuse - if the horn's good it should sound.
Removing the Horn
The horn sits towards the front of the screenwash bottle (picture from screenwash bottle replacement guide)
Jack the car up and place it onto stands.
If you look up and under the car, just in front of the right hand (passenger side in the UK) arch you should be able to see the horn
Assuming you've got a socket extension bar (or bars) long enough, you'll simply be able to reach up and undo the mounting bolt. You can probably only fit one arm into the gap at a time, but that's all you need.
If you can't reach (or if your arm doesn't fit), then you can also undo the wheel arch liner and pull it to one side as described here - my arch liner fixings were seized in place so I decided it was better not to disturb them.
Reach up and disconnect the electrical connector - there's a tab on one side of it that you need to squeeze whilst wiggling the connector off.
Use a 13mm socket to unscrew the mounting bolt and then pull the horn down the bolt and out of the car.
Fitting a non-GM horn
I purchased a generic horn with spade connectors from the internet: GM horns are quite expensive and don't seem to last.
However (as you might have noticed in earlier pictures) the existing horn has a special connector, so a non-GM horn can't be installed without adjustments.
The simplest solution would be to cut the connector from the loom and solder on some spade connectors, but cutting into a car's loom is a very, very, very bad idea - especially when there's no need to that kind of damage.
Instead, we can unclip the connector from the back of the old horn - there are 3 small tabs holding it on.
Inside are 2 small metal pots which would wrap around the horn's contacts, push some wires into these and solder them into place
Wrap it in some black nasty
Use a seperate strip of electrical tape for each side so that any trapped moisture can't end up forming a short.
Remove the mounting bracket from the old horn by using a 10mm socket to unscrew the retaining bolt and then fit the adapter to the new horn
Re-fitting is essentially the reverse of removal, with a little bit more swearing.
Slide the horn up and into position, when you remove your hand it should hang roughly in place: because its weight is to one side of the mounting bolt friction holds it in place.
Put the nut onto the end of the bolt and tighten it down until the horn is secured in place
Reach up and click the electrical connector into the adapter
Go and press the steering wheel, you should be rewarded with the sound of your new horn.
Reinstall the arch liner (if you disturbed it) and then put the car back on the ground.
The horn on a Vauxhall Corsa E is relatively easy to access without needing to remove the bumper. Because of the way that the horns are made, it's also reasonably straight-forward to fit a non-official horn by cannibalising the old horn for parts to make an adapter.