Sounds like your head unit is aware of the bluetooth module then. Do you have a 'Telephone' menu on the MFD? I have a 3C8 module (9wZ, similar to 9w7 as you have) and I initialize the pairing from the MFD, not from the phone. Are you able to do so? I also have a 'Visibility' option, do you have that so you can check that it is enabled? Don't know why it would have been disabled in the first place, but anyway...
My last suggestion is to physically inspect the wiring harness at both ends to look for damaged or bent pins, do a continuity check etc.