I burned the Comfort VAN data bus B wire

[bokis]

While trying to enable the CD changer option and install AUX plug I shorted some pins on the back of the RD3 radio and probably burned the Comfort VAN data bus B wire - pin 3 or pin C, depending on the image source (continuity test shows it's short to the ground).
The car turns but it won't start, display is dim, barely readable, while the warning lights are bright. I tried doing a BSI reset procedure several times but nothing changed.
Before coming here to ask for the advice I asked AI and it says I need to cut the wire behind the ISO-A (black) connector (which makes no sense to me) or to cut it in the door loom. Apparently, after cutting the burned wire, the car should start normally but the radio will be dead untill I replace the wire.

Any thoughts on the problem, where should I cut the wire and please post images if you have them.

Thank you

Edit: Forgot to mention it is a Xsara Picasso 1.6hdi 2004 (january)

[xantia_v6]

I would be a bit sceptical of that advice.
It is typical that modules connected to the bus will have protection diodes to minimise damage if excessive or reverse voltage is applied. If too much current flows through the diode then it will become a permanent short circuit to ground.
You should unplug every module connected to the bus to determine which one(s) have failed.
If you isolate a faulty module, then it should be repairable.

[wheeler]

Have you double checked all the fuses??
Cant see you 'burning out' a data wire, my money is on a blown fuse.

Please don't follow any of the AI advice

[wheeler]

Have a look here > viewtopic.php?p=647984&hilit=VAN+fuse#p647984

[bokis]

I checked all the fuses and they were all fine. After that I bypassed the Comfort DATA B wire that Lexia was pointing to be the culprit but now I get new errors. The next step I plan to do is to bypass the Comfort DATA wire as well and do another BSI reset (I have probably done 5 of those today and still can't start the engine, it turns but does not start). Battery light is ON (battery fully charged over night, just in case) and the main display is still dimmed.

I attached the 3 latest screenshots from Lexia.

[wheeler]

Can you confirm fuses 4, 14 & 15 in the BSI have 12v on both sides with ignition on?

[bokis]

Can you confirm fuses 4, 14 & 15 in the BSI have 12v on both sides with ignition on?

With the ignition on F4 has 12v on one side, 2.45v on the other. F14 and F15 have 12v on both sides.

[wheeler]

Can you confirm fuses 4, 14 & 15 in the BSI have 12v on both sides with ignition on?

With the ignition on F4 has 12v on one side, 2.45v on the other.

Unless im missing something that means the fuse is blown?? (or there is a huge volt drop across it)
If the diagram in the other post is the same as yours that fuse is the permanent supply for the radio & com2000 unit.
No power to the com2000 = no start
This would also explain the no comms with the switch module at the steering wheel.

I'd be amazed if this wasn't just a blown fuse.

[bokis]

OMG! When I was testing the F4 for continuity it was beeping, when I took it out it was evident it was burned. Gremlins. New 20A fuse is in, car started. It still shows the airbag error but I will connect Diagbox to it and resolve it...

Thank you so much @wheeler and everyone

[bokis]

Now the only errors that are reported on the dashboard and main screen (and in Lexia) that airbags are not functioning. I will try to resolve this today.