How to install front dash speakers in 2007 tailblazer?

https://www.google.com/search?q=2007+chevy+trailblazer+radio+wiring+diagram

and specifically

https://www.modifiedlife.com/2007-chevrolet-trailblazer-radio-wire-color-codes/

..

Trace the wiring back up through the grommet going through the hatch into the top. This is an area to look for broken wires.

Need a special speaker, 4" max size, for the front as it has an angle tab to match the molded dash. Try Crutchfield as I bought my replacement Pioneer form them decades ago and it sounds so much better. They provide it with correct plug installed. a 10 minute job.

Yes, loose connectiosn, internal integrated amp device burned, bad ground or speakers go to bad.

there is an amp usually built into the factory head unit or mounted in the dash behind the head unit. I would try running a new wire straight from the back of the stereo to the speaker and see if it works. if it does then you have a broken wire and need to run new ones

BLACK - GROUND (-12v)
YELLOW - IGN (+12v WHEN CAR IS ON)
ORANGE - MEMORY (+ 12v ALWAYS ON)
GRAY - BACKLIGHT (ON WITH DASH LIGHTS)
BROWN - DIMMER
PINK - POWER ANTENNA (MAY NOT BE THERE)
LIGHT GREEN/DARK GREEN - RIGHT FRONT SPEAKER +/-
TAN/GRAY - LEFT FRONT SPEAKER +/-
DARK BLUE/LIGHT BLUE - RIGHT REAR SPEAKER +/-
BROWN/YELLOW - LEFT REAR SPEAKER +/-

Use a voltmeter or test light to tell the difference between the gray dash light wire and gray speaker wire, and yellow power wire and yellow speaker wire.

Did it fail while you had vehicle, or like this when you bought it? Could be bad radio or wiring harness was chopped up when previous owners had an aftermarket radio installed. They probably just slapped the OEM radio back in when selling car. And didn't put all the OEM wiring back in.

1998 Chevrolet Blazer S-Series Stereo Wiring Constant 12V+ Orange Switched 12V+ Yellow Ground Black Illumination Gray Dimmer Brown Antenna Right Front Front Speakers 6 1/2" Doors Left Front (+) Tan Left Front (-) Gray Right Front (+) Light Green Right Front (-) Dark Green Rear Speakers 6 1/2" Rear Doors Left Rear (+) Brown Left Rear (-) Yellow Right Rear (+) Dark Blue Right Rear (-) Light Blue

when mine stopped working,the right speaker, i removed the door panels then swapped the speakers. and still the right speaker didnt work. so i got a radio from a junkyard and installed it. and now all speakers work fine.