Hi all, I have a question.

For some reason my horn doesnt work when I start the car if it has been sat for about half hour I'm guessing the time all the electronics power down properly.

When I start the car there is no horn nothing at all. If I turn the car off and back on at any point the horn works fine.

I don't think it's a battery problem as I drove 1000 miles across Europe and it happened at a service station. My first thought was the relay switch so I changed that and also reseated the fuse but this doesn't solve the issue.

What would people's next step be or if this is a common fault that people may know about.

Many thanks for all replys

Hi,

I don't think it may be a battery, relay or fuse issue. Otherwise it won't come back on 'hot start'

I assume it could be related to the pneumatic part of the horn, having a pressure loss. On 'cold start', the pressure has completely dropped down leading to a horn not working. On 'hot start', the pressure loss is too slow and the horn still works.

This is only a theory, not sure it is what really happens...

13 minutes ago, Bap33 said:

Hi,

I don't think it may be a battery, relay or fuse issue. Otherwise it won't come back on 'hot start'

I assume it could be related to the pneumatic part of the horn, having a pressure loss. On 'cold start', the pressure has completely dropped down leading to a horn not working. On 'hot start', the pressure loss is too slow and the horn still works.

This is only a theory, not sure it is what really happens...

Thanks for the reply. So that part is in the horn itself located behind the bumper right.

3 hours ago, fodbrothers said:

Hi all, I have a question.

For some reason my horn doesnt work when I start the car if it has been sat for about half hour I'm guessing the time all the electronics power down properly.

When I start the car there is no horn nothing at all. If I turn the car off and back on at any point the horn works fine.

I don't think it's a battery problem as I drove 1000 miles across Europe and it happened at a service station. My first thought was the relay switch so I changed that and also reseated the fuse but this doesn't solve the issue.

What would people's next step be or if this is a common fault that people may know about.

Many thanks for all replys

normally the horn is wired via the bcm [ body control module / basically the bcm is a pcb which controls things.

if you can, check the wiring diagram to confirm the horn is wired via the bcm as that is normally the way VAG do it.

as with all intermittent faults though you will need to test things while the fault is actually happening ie look for a live feed or lack of a live feed to the horn from the bcm

6 hours ago, fodbrothers said:

Thanks for the reply. So that part is in the horn itself located behind the bumper right.

I have my MY2022 Kodiaq for less than one month. I didn't have the time to have a close look under the bonnet yet, sorry...

But if as on many other VAG models, this could be behind the front bumper, indeed.

Other possibility, horn wires damaged by a rodent, leading to intermittent fault...

Edited 10 May, 20251 yr by Bap33

14 minutes ago, Bap33 said:

I have my MY2022 Kodiaq for less than one month. I didn't have the time to have a close look under the bonnet yet, sorry...

But if as on many other VAG models, this could be behind the front bumper, indeed.

Other possibility, horn wires damaged by a rodent, leading to intermittent fault...

I dont know if it would be the horn as Kodiaqs have 2 horns so im thinking it may be somthing else.

its just strange that it will work if you start the engine again even straight away.

I feel skeptic about an electrical cause leading to a common fault mode on both horns at the same time...

This gets me back to my pneumatic theory, then... 🤷‍♂️