I can't tell you exactly how the lumbar support works on the B6, but on my B5.5 there is a noticeable difference between the two extreme settings; which I'll call "full soft" and "full firm." The B5.5 system works through a system of springs/wires which, as you stated, are prone to failure. The lumbar support system on my B5.5 failed and I had to pull up the rear portion of the seat cover and was able to switch out the wire which was snapped. I had to acquire the part from a salvage yard as the faulty part is not available separately. After the part was switched both seats functioned identically which I would assume is also the case with the B6 seats, both should resemble each other.
If the B6 is the same as the B5.5 in the sense the part is not available separately, maybe the problem lies with the dealer not wanting to replace the entire seat assembly for one part. Maybe speak to the dealership again and show them the difference between the two seats.
Be persistent and good luck.
If the B6 is the same as the B5.5 in the sense the part is not available separately, maybe the problem lies with the dealer not wanting to replace the entire seat assembly for one part. Maybe speak to the dealership again and show them the difference between the two seats.
Be persistent and good luck.