Alarm- siren problem

[Luckyluck]

Hi guys,
I'd like to ask what to do or if you have any idea where to look or point me the right direction. I've bought 2 months ago 2014 Seat Leon estate and I've found out later on that my siren is not working. When I triggered the alarm ( I was sitting inside the car) only the hazard lights went off, no sound from siren. I've plugged it on computer and scanned it with vcds and got the error - no communication with alarm horn/siren you can see it on attached picture). So I bought from eBay a replacement from 2018, swapped it and tested but I got same outcome like with my original siren..so I thought, ok probably o got lucky and the replacement I bought was probably "dead" as well. So I bought another siren this time manufactured in 2022 ..replaced it but I got the same issue. So my question is where should I look now, because obviously both replacement sirens are fine but problem is on my car. Anybody has wiring diagram or point me somewhere what could solve my problem please?

 

[grabania]

My guess is that's the issue with fuse. Check SB20 fuse in engine fusebox

 

[Luckyluck]

My guess is that's the issue with fuse. Check SB20 fuse in engine fusebox

View attachment 40823

Just checked but that fuse is ok

 

[grabania]

So you can check whether the cables are fine:
- between 31st pin in 46pin B connector in BCM (A2 in the photo) and 1st horn pin
- between earth point marked on photo and 2nd horn pin
- between fusebox and 3rd horn pin

Full diagram here (H12 is the alarm horn):

 

[Luckyluck]

So you can check whether the cables are fine:
- between 31st pin in 46pin B connector in BCM (A2 in the photo) and 1st horn pin
- between earth point marked on photo and 2nd horn pin
- between fusebox and 3rd horn pin

View attachment 40834 View attachment 40838

Full diagram here (H12 is the alarm horn):

View attachment 40836

Thank you, I'll check it out. Just a quick question..my Leon is Rhd car, so the BCM is still on left side same like on the picture from LHD car?

 

[serdar_18fr]

Hi guys,
I'd like to ask what to do or if you have any idea where to look or point me the right direction. I've bought 2 months ago 2014 Seat Leon estate and I've found out later on that my siren is not working. When I triggered the alarm ( I was sitting inside the car) only the hazard lights went off, no sound from siren. I've plugged it on computer and scanned it with vcds and got the error - no communication with alarm horn/siren you can see it on attached picture). So I bought from eBay a replacement from 2018, swapped it and tested but I got same outcome like with my original siren..so I thought, ok probably o got lucky and the replacement I bought was probably "dead" as well. So I bought another siren this time manufactured in 2022 ..replaced it but I got the same issue. So my question is where should I look now, because obviously both replacement sirens are fine but problem is on my car. Anybody has wiring diagram or point me somewhere what could solve my problem please? View attachment 40822

According to the diagram, a 3-pin connector plugs into the alarm horn (H12)
Violet/white cable goes to J519 (BCM/Onboard supply unit) --> Pin 31 in the 46-pin connector.
Brown cable goes to the engine wiring harness where it gets a ground connection
Red/violet cable to goes to fuse holder B - SB20

 

[Luckyluck]

So finally weather was good after many days of pouring rain and I got the time to check the wiring from siren connector. Here are my findings..I've "beeped" all 3 wires, so the ground wire is ok, red/violet cable to fuse 20 in engine fuse box is ok but it seems like Violet/white cable which goes to J519 (BCM/Onboard supply unit) --> Pin 31 in the 46-pin connector appears to be broken somewhere. I'll try to connect it temporarily so I'll be able to test the alarm if the siren will be working and if it will works ten I have to figure out how I will bring the cable in through the wall between engine and cabin but I doubt it because there's

 

[Luckyluck]

So finally weather was good after many days of pouring rain and I got the time to check the wiring from siren connector. Here are my findings..I've "beeped" all 3 wires, so the ground wire is ok, red/violet cable to fuse 20 in engine fuse box is ok but it seems like Violet/white cable which goes to J519 (BCM/Onboard supply unit) --> Pin 31 in the 46-pin connector appears to be broken somewhere. I'll try to connect it temporarily so I'll be able to test the alarm if the siren will be working and if it will works ten I have to figure out how I will bring the cable in through the wall between engine and cabin but I doubt it because there's no o

 

[Walone]

According to the diagram, a 3-pin connector plugs into the alarm horn (H12)
Violet/white cable goes to J519 (BCM/Onboard supply unit) --> Pin 31 in the 46-pin connector.
Brown cable goes to the engine wiring harness where it gets a ground connection
Red/violet cable to goes to fuse holder B - SB20



View attachment 40837

View attachment 40839

@serdar_18fr , a bit off topic, is there an index for finding the relevant wiring diagram? I have the PDF's, over 3000 pages!! trying to find the diagram i want is a nightmare!

 

[serdar_18fr]

@serdar_18fr , a bit off topic, is there an index for finding the relevant wiring diagram? I have the PDF's, over 3000 pages!! trying to find the diagram i want is a nightmare!

I have a collection of workshop manuals that contains 48 PDF files.
All of those have "Contents" pages, except the one that contains wiring diagrams!
Even the name of that file does not look like a document where you would look for the wiring diagrams : "Basic equipment"
And it has duplicate pages for each of the different build periods, it is really a nightmare to discern what you're looking at.

 

[Walone]

I have a collection of workshop manuals that contains 48 PDF files.
All of those have "Contents" pages, except the one that contains wiring diagrams!
Even the name of that file does not look like a document where you would look for the wiring diagrams : "Basic equipment"
And it has duplicate pages for each of the different build periods, it is really a nightmare to discern what you're looking at.

I'm glad I'm not the only one with this problem, I thought it was me being dumb!!

 

[Luckyluck]

So finally weather was good after many days of pouring rain and I got the time to check the wiring from siren connector. Here are my findings..I've "beeped" all 3 wires, so the ground wire is ok, red/violet cable to fuse 20 in engine fuse box is ok but it seems like Violet/white cable which goes to J519 (BCM/Onboard supply unit) --> Pin 31 in the 46-pin connector appears to be broken somewhere. I'll try to connect it temporarily so I'll be able to test the alarm if the siren will be working and if it will works ten I have to figure out how I will bring the cable in through the wall between engine and cabin but I doubt it because there's

So finally, new wire pulled to BCM, all working now..thank you all guys for your help