For months the bluetooth has worked extremely well, yesterday the MID froze with "INCOMING CALL" displayed, all attempts to disconnect the phone has failed. Audio/Voice is not working either. The T637 works in standalone mode.
Any ideas? Has the HFL module failed?

 

I don't think it's the phone. The HFL froze. Look up which fuse the HFL is on, and pull it out to reset it. If that doesn't work you should take it to the dealer, because it's probably broken/crashed.

 

The fuse for the HFL is not indicated in the manual, checking other threads its fuse # 6--Interior Lights. Removed the fuse and re seated it and all is working fine.

 

Good to hear that.
What do you do when your computer freezes? You cut off power to it, and restart it. The same concept applies here. That's all the MID, HFL and Navi are; computers.