Car Stereos: low volume, bose amp, windshield posts

Question
I have a 2006 Tahoe with a Bose stereo system.  I have to turn the radio up to full volume, to get a descent listening volume out of it...which is still very low.
I noticed the front speakers, on the front windshield posts, are not producing any sound either, but the rest of the speakers are working fine.
I know the system has a separate Bose amp and I'm leaning towards it as the problem.  Any ideas???

Answer
Hi Mark,

It sounds to me like a connection somewhere in the vehicle has become loose.

Troubleshooting issues like this one are always tough.  The issue could be the headunit aswell.  Especially with your front posts being out, which are likely being powered directly off of the HU.

Justin