Some great info there. Confirms my(and others' ) thoughts of resistors stepping down the speeds inside the motor.
If you dont mind would you be able to measure the resistance of each of the resistors there? I'm thinking of making another loom with the same resistances to mimic the operation with slimline fans. My current setup means i have speed 1 = 1 fan, speed two = 2 fans slow speed from fan control module, speed three = 2 fans high speed from fan control module
Your skills are more than sufficient to rebuild it to a better standard than it was originally!