Unless you can get to the aux input to plug in a cable for an mp3 player you are stuck with CD audio only.
www.trailvoy.com
The player is probably broken.
You can listen to mp3's in a Trailblazer. There are audio devices that you can attach to your lighter in order to play them.
Check the cd player for items which may have been shoved into the player. If this is not the case the laser may have burnt out, a wire could be loose, or something else may have broken.
Up to 2002, Trailblazer was just a trim package for the Gen. 2 Chevy Blazer. V8 swaps with a small block are pretty common in those. I had a 97 Blazer (without the Trailblazer package), and I actually ran a 6.0 with a 4L80E transmission.... mind you, this is not a simple plug and play swap.. I had to change the engine mounts, modify the engine compartment, repin a bunch of wiring harnesses, and run electric fans. But it's certainly doable. Not sure about the 2003+ TrailBlazer, although some were offered with a 5.3 V8, so it would certainly be feasible to expect that it could be done.
Edwin Almonte debuted on July 7, 2003 and played his final game on September 10, 2003.
Nate Bland debuted on May 5, 2003 and played his final game on June 27, 2003.
Mark Budzinski debuted on August 3, 2003 and played his final game on August 8, 2003.
Juan Cerros debuted on September 8, 2003 and played his final game on September 28, 2003.
Jim Chamblee debuted on August 24, 2003 and played his final game on August 25, 2003.
Travis Chapman debuted on September 9, 2003 and played his final game on September 9, 2003.
Anthony Ferrari debuted on June 7, 2003 and played his final game on June 18, 2003.
Roger Deago debuted on May 10, 2003 and played his final game on May 15, 2003.