Interesting aircraft wiring

My new Skoda is becoming increasingly unsettling.
When wiring the original AHK, I noticed that the AHK control unit uses three fuses. So, I got a schematic diagram to get a better understanding of this whole thing.
This applies to the entire G5/6 series. The fuses used are 2 x 15A and one 20A. Everything with a cable cross-section of 1.5mm². 20A at a cable length of 5 meters is already quite daring...!
It's even surprising that pin 9 is connected to a constant positive voltage. This pin is connected to the trailer control unit (located in the vehicle's rear) with a 2.5mm² wire, which runs to the socket (approximately 1.5 meters long). All the wiring connections up to the AHK control unit are only using 1.5mm² cable.

I wonder what the point of all this nonsense is.
Protecting a power supply with a 20A fuse and then using 1.5mm² wiring seems risky. If you connect a caravan with a refrigerator (150W, which is 12A) to it, the 1.5mm² supply cable to the trailer connector will likely get quite warm. Quite apart from the voltage drop that will inevitably occur on such a long cable run.

The only conceivable solution would be to use two 1.5mm² wires in parallel to supply the voltage at pin 9. Unfortunately, that is beyond my knowledge.


In building G4, everything extends all the way to floor Fz. The cable with a cross-sectional area of 4mm² is run and then connected to the outlet using a cable with a cross-sectional area of 2.5mm².
"With the Forester, I wired it like that to minimize losses."

hiho


'It seems to be normal for VAG vehicles... I also encountered this in a few places when installing the OEM auxiliary heating system in my Scirocco. On one side of the cable, it's 1.5mm² up to a connector, and on the other side, it's 0.5mm² or the reverse! I really questioned myself a few times because I couldn't believe it was supposed to be like that.'