Dear ksu72--  Don't worry.  With global warming like we are having in Boston you won't see the temperture below 40 degrees much anymore.  But for an immediate answer to your question I don't see why you haven't brought your 2004 Silverado back to the dealer for warranty service.  Either your speaker is damaged and will be replaced or there is a bad connection and it will be repaired.  Take advantage of the warranty.  You paid for it.   Good luck from Bovan.

Already had it back in to dealer, they seem clueless.  That's why I thought maybe someone else had experienced a similar problem.  Thanks anyway.

Dealer seems clueless on problem.  Thought someone else may have experienced similar problem.