Car Stereos: 2001 suburban, center speakers, rear trunk

Question
Lost almost all sound from front door speakers and rear trunk speaker.  Get only very muffled sound but not completely dead.  Normal sound from center speakers in doors and the two tweeters all the way in the back up high.  How do I troubleshoot?  Is it most likely head unit, speakers or something else?

Answer
Hi Bill,

It sounds like wiring.  Check the connections to the speakers, and at the back of the stereo.  Make sure everything is tight, and there's no corrosion.  (The inside of doors are notorious for letting moisture in, and rotting the connections).

If that doesn't fix it, then unfortunately, you're looking at trial and error: switch speakers to different locations.  If speakers that were previously broken start working elsewhere, replace the deck.  If the same speakers have issues in different places, replace the speakers.

Justin