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Thank you so much Ciclo. I think you are the most helpful person in the World.
I am sure that many upgrades and fixing of problems could not happen without your help.
I am so glad I joined this forum.
Thanks a lot again.

Now I got a new sensor from my local store. I will try to replace it now.

You're welcome...

Hopefully we get lucky and the problem is fixed by changing the switch/sensor.
Please tell us the result, thank you.

Hi. Unfortunately after over an hour fight, I give up.
I couldn't screw out the screw. The sensor is located up side down and there is so different acces to the screw.
I will need go to garage tomorrow ask mechanic for this job.

Do not worry, it is normal for this to happen, the mechanic will solve it quickly,
they usually have the right tools and experience to access the screw easily.

The important thing is that your brake lights come to life in any way.

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If you want and it is possible, take an image so that we can see the situation of the sensor.
Maybe we can figure out how to access the screw ...

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On the other hand, you may have a strong magnet that you can add near the tip of the tool that will hold the screw so you can thread it into the body of the master cylinder.
You must be meticulous and avoid dropping the screw while making this new attempt.

There is everything up side down. Impossible to see the screen from top. Any what I could do, was intuitively put screw driver into the screw, but did have room to use power to screw it out.
I gave it up, because I was afraid I break the screw and then I do more problems.

Ok, thanks for the images, you did the right thing, it is better not to make the situation worse.

For LHD vehicles it is somewhat easier to access the screw.

That is strange. All movies and reviews I met, people say that they have brake lights on all the time when sensor is broken.
In my case , I don't have brake light at all

In case you can draw any conclusions ...
- The trigger/activation signal is sent from the sensor to the BCM at pin T73a/43 (IN). ... the engine unit receives two signals from this sensor (G100).
- BCM power for brake lights and turn signals is +30 (bat) ---> fuse 20 (Ibiza) ---> T73b/13 (IN).
- The BCM then sends power to all the brake lights through T73b/16 (OUT).

I understand that.
I checked fuse 20 with is fine, so I hope that new sensor will resolve the problem. Otherwise I will be in trouble.

Just for upgrade, mechanic exchange the sensor, but it doesn't help. Still no brake light.
I have to bring my car to electrician for checking

ciclo wrote: Sun Jan 09, 2022 7:19 pm In case you can draw any conclusions ...
- The trigger/activation signal is sent from the sensor to the BCM at pin T73a/43 (IN). ... the engine unit receives two signals from this sensor (G100).
- BCM power for brake lights and turn signals is +30 (bat) ---> fuse 20 (Ibiza) ---> T73b/13 (IN).
- The BCM then sends power to all the brake lights through T73b/16 (OUT).

I wonder why the sensor sends 2 signals to engine unit? Does it have impact on brake light?
Following electrical diagram, it shows that sensor sends signal straight to BCM to T73a 43, which should give impuls to pin T73b 16 , to make brake light working.

It is not related to the brake light.
The engine electronics must know both the brake activation and the brake pedal position... it's just that the same wire/signal is used for both the BCM and the ECU.

So, I have no idea where is problem now after replacing the senor?

Question, if I combine pin 3 and 4 in sensor connector should it tiggle signal to bcm T73a43 ?

Do it ... remember ignition switch ON - engine OFF.