Thanks to @witek_77 for the information: https://www.seatcupra.net/forums/threads/retrofit-washer-fluid-level-indicator.474960/post-5049770
What you need:
1. Plug 1J0973202 for washer fluid level sender (G33 on the diagram)
2. 2x 2 meters of 0,3...0,5mm2 wire
3. Tesa automotive PET cloth tape (51007)
4. One MQS female pin for T46B plug (for pin 28, pin 19 just attach to the wire already there)
5. Something for coding (obd11, Odis etc)
6. Tank already have built-in fluid level sensor.
You need to disconnect and take out the battery, remove the left front wheel, unscrew the front part of the wheel arch, unscrew the plastic under the steering wheel. Remove the middle plug (B) from the BCM (T46b), unplug it, connect the wires to pins 19 and 28, pull it through the rubber seal on engine firewall to the engine compartment, lead it somehow to the washer tank (I led it through the top and went down behind the lamp just like the original washer harness), and connect the plug.
Coding:
1. 09 central electrics (SFD locked)
2. Adaptations
3. [VO]_HW_verbau
4. insufficient washer fluid > change from "not installed" to "installed"
What you need:
1. Plug 1J0973202 for washer fluid level sender (G33 on the diagram)
2. 2x 2 meters of 0,3...0,5mm2 wire
3. Tesa automotive PET cloth tape (51007)
4. One MQS female pin for T46B plug (for pin 28, pin 19 just attach to the wire already there)
5. Something for coding (obd11, Odis etc)
6. Tank already have built-in fluid level sensor.
You need to disconnect and take out the battery, remove the left front wheel, unscrew the front part of the wheel arch, unscrew the plastic under the steering wheel. Remove the middle plug (B) from the BCM (T46b), unplug it, connect the wires to pins 19 and 28, pull it through the rubber seal on engine firewall to the engine compartment, lead it somehow to the washer tank (I led it through the top and went down behind the lamp just like the original washer harness), and connect the plug.
Coding:
1. 09 central electrics (SFD locked)
2. Adaptations
3. [VO]_HW_verbau
4. insufficient washer fluid > change from "not installed" to "installed"