I found this thread really helpful when tracing through a problem with my fan controller (works on 1, 2, 3, not working on 4). Unplugging the cables inside the dash is a little daunting because you cannot see what you are doing. I did manage to get my camera inside the dash to take this photo - it isn't my best photo but may be helpful to others to better understand what they're groping about for.
As I expected, pin 4 was melted. I cleaned up the connection and have all 4 settings working again, but I'll order a replacement loom to finish the job properly.
Thanks again for this thread,