If you receive a 2010 or later Subaru Legacy or Outback model with a customer concern of no audio volume while using their Bluetooth hands-free, inspect the left front speakers for proper operation (both the door and dash speakers).
This can be done using the fader and balance functions from the audio head unit to isolate the output to the left front. If there is no sound, the speaker may have failed, or you may find a pinched wire, loose connection or possibly an amplifier problem if it is a Harmon-Kardon equipped vehicle.
In addition, if there is no audio output at all from the audio unit, a pinched speaker wire is the first thing you should inspect.
The Techline has received reports from the field involving pinched speaker wiring, primarily (but not limited to) in the doors as the cause of the concern.
Another area to inspect for wiring trouble is in the “A” pillars for the tweeters. A green wire shorted to ground reportedly causes both front tweeters and the subwoofer to be inoperative.