Thanks.
Ok, ok, now I understand some technical questions related to the VIN and the diagrams and that are not important to be explained.
Well, assuming that the new CAN lines will make the 7H0 BCM better manage the control units in your Ibiza, the next step is to feed the 7H0 BCM so that it can subsequently exercise full control over the low/dipped beams. Currently your dipped beams are managed/powered by relay J331.
Relay J331 is activated according to headlight models.
- From light switch ... for H7 dual headlights.
- From light switch + steering combination switch (HB/LB stalk/lever) ... for H4 headlights.
With 7H0 BCM this relay is not necessary (it must be removed, first remove and
isolate the blue wire on the light switch T17/7), however this relay (holder/adapter) receives a RED power wire that is perfect for you to feed two pins of your 7H0 BCM, T73a/63 and T73b/68, from this RED wire.
Note (minor): These two new red/white wires also feed other pins on the 7H0 BCM (lights and BCM internals), which will cause some diagnostic faults. Some faults can be corrected by coding, but others cannot, and new wires must be installed to avoid diagnostic faults. Don't worry at this time, it has an easy solution.
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The next step is to connect directly to the BCM connectors the Yellow and Yellow/Black wires that you remove from the output of the SC57 and SC58 fuses. The following diagrams shows the assignment.
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The next step is to add a new 0.5mm2 wire from the SC36 fuse output to T73a/62.
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The next step is to add the headlight control relay that will make automatic low beam control possible. This relay is called J828.
I show you in images/diagrams the identification and what you must do to install this relay.
Indentification:
Installation:
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The next step is to add 5 new wires. Light switch - BCM - Dimmer. 58 signal, 58 power supply (58d), License plate lights, Auto function.
Note: If in your previous wire installation in the light switch you have done something different or if any of these 5 wires are joined together to achieve some trick

,
your installation is not correct.
To install these 5 new wires follow the order that I have established in the following diagram (download the image to see it enlarged).
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The next step is to have the reversing light (back-up light) and rear fog light under BCM control.
To avoid confusion, I explain what you should do instead of showing it in diagrams.
Reversing light:
Only for manual gearbox, for DSG it is not necessary to do this step.
Explained for LHD models. For RHD models, it is the same but in the opposite taillight.
- Remove and isolate the original T6/4 wire from the right taillight connector.
- Add a new 0.5 mm2 wire from T73b/12 to T6/4. ...(5.5 - 6.5m)
Rear fog light:
- Remove the original wire T17/9 from the light switch and splice a new 1.0mm2 wire to this original wire, take/run this new wire up to T73a/6 BCM black connector.
- Add a new 0.5mm2 wire from T17/9 to T73b/43 BCM white connector.
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Daytime running lights (DRL) (TFL -Tagfahrlicht-) for retrofitted 6P halogen headlights (PQ26) on an Ibiza 6J with an adapted BCM Max (PQ25).
Installation:
From Light switch - to BCM.
- Install a new 0.5mm2 wire from T17/3 light switch connector to T73b/29 BCM white connector.
From BCM - to 6P Halogen headlights with LED module.
The 6P Halogen headlights LED modules receive two power signals from the BCM, the one dedicated to the DRLs and the one dedicated to the Sidelights/Parking Lights.
Left headlight (two new 0.5mm2 wires).
DRL.
- Install a new wire from T73b/3 to T10/4 in headlight connector.
Parking/Side light.
Edition, November 11, 2021.
Do not perform the next step for parking lights. Reason here
viewtopic.php?p=587292#p587292
- Remove and
isolate original T10/10 in headlight connector.
- Install a new wire from T73b/5 to T10/10.
Right headlight (two new 0.5mm2 wires).
DRL.
- Install a new wire from T73
a/5 to T10/4 in headlight connector.
Parking/Side light.
Edition, November 11, 2021.
Do not perform the next step for parking lights. Reason here
viewtopic.php?p=587292#p587292
- Remove and
isolate original T10/10 in headlight connector.
- Install a new wire from T73b/6 to T10/10.
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After doing this installation/adaptation it is necessary to code the BCM Max.
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Editing ... please wait.. step by step, do not do anything at the moment until you know the results of the new CAN lines ... (SOLVED!)
I will support this info with diagrams and images.