Citroen C2 VTS Code Horn not working

[charliesilva027]

Hello everyone

I recently made a post about how to replace my alternator and thanks to the help of mickthemaverick was able to get it figured out. to cut a long story short I have a C2 code edition and have recently overhauled it with new timing belt water pump alternator and brake disc and pads and all fluids along with that stuff, went for the MOT and failed on no horn my fault for not checking before but you live and you learn I have taken the horn off and there was a heavily corroded pin this has now been fixed and have tested the horn and it is working. the issue is the horn isn't working when on the car have checked the fuses and they are all good, I have voltage going to the horn as well so that's not a issue, my current theory is that the switch for the horn on the steering wheel isn't working and not flipping the ground like it should because I cant see that happening with my multimeter when I press the horn. I have notice the previous owner has been in the fuse box in the past and have tried to research the interior fuse box diagrams because I'm not sure all fuses are there that should be because everything online doesn't have the same fuse box that I seem to have i think this may also be playing into why the radio isn't working I need to set the date on the radio but none of the buttons do anything.

Sorry for the lengthy question but if anyone has had this issue before or has any ideas I'm all ears and if anyone has a picture of what the interior fuse box should look like that would be amazing.

[mickthemaverick]

If you can post a picture of your fusebox it may jog a memory or two. The method is in the link below:

viewtopic.php?p=516529#p516529

[charliesilva027]

I have uploaded both fuse boxes just in the off chance that there is a issue with either. i have also done some further testing and the horn switch is also working with no problem and there is no corroded connections anywhere but for some reason the horn will not activate.

[wheeler]

You have ruled out a faulty horn by applying 12v & earth directly to the horn?
You say there is voltage at pin 1 of the horn connector when you press the horn? best to check this with a bulb (not an LED) , just because it is showing voltage does not mean there is enough current.
If there is voltage (with enough current) then it has to be an earth fault at the horn. Maybe add an new earth to pin 2 of the horn.

[charliesilva027]

Yes I have applied voltage directly to the horn and it is working, the way the horn works on this car is that there is a constant 12v supply to the horn and when you press the horn it should flip the ground which then activates the horn I'm not seeing this flip happen the voltage is just remaining the same. I will give you suggestion with the bulb a shot got a new MOT this coming Friday so will be working on it everyday after work until I get it sorted.

[charliesilva027]

I have also got hold of the official wiring diagrams for the horn I don't know what the rules are for that on this forum so I wont share then at the moment but I will be going through the whole system to see what is playing up. if it is ok for me to upload the images of the wiring diagrams I have then I can do that as well.

[wheeler]

Please share the wiring diagram you are using as the one im looking at shows a constant earth & a live switched by an integral relay in the under bonnet fuse box.

[charliesilva027]

I think you are right wheeler I was getting too focused and not looking at the diagrams properly there shouldn't be a constant 12v according to the wiring diagrams. i have both the CAN CAN and CAN VAN versions as I'm not 100% sure which version I have.

CAN CAN

CAN VAN

[charliesilva027]

I have noticed that the previous owner has replaced the original fuse box and left it in the boot. there is the possibility that this fuse box could also be faulty.

[wheeler]

Looking at your under bonnet fuse box this is a CAN CAN car

[charliesilva027]

But if the relay has failed open and is sending the constant 12v then the horn should be on at all times but it is not.