My speakers at back does not work on my chevy 2007

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/

..

First you need to have EBCM - electronic brake control module check for DTC'S - diagnostic trouble code's . If the light is on there is a code stored . I think most part stores can do this and for free . After you find out what code is stored , looking up that code in service repair information for diagnostic trouble shooting chart would be next step . There are a few codes too.
DTC C0035 or C0040
DTC C0045 or C0050
DTC C0110
DTC C0131
DTC C0161
DTC C0186
DTC C0196
DTC C0201
DTC C0240
DTC C0241 or P0856
DTC C0244 or P1689
DTC C0245
DTC C0283
DTC C0287
DTC C0290 or C0292
DTC C0455
DTC C0550
DTC C0558

Find the code do the diagnostic's , fix the problem , wiring issue's , a sensor , bad module ,what ever it is . The light will go out then . Here is a sample of code discription .
• DTC C0035 Left Front Wheel Speed Sensor Circuit
• DTC C0040 Right Front Wheel Speed Sensor Circuit

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Chevy Trailblazer 2002 2009 Factory Service Workshop repair manual

for the best solution of your problem visit this site :))

Follow the radiator hose back to the engine on the top side. Where the hose connects to the engine is the thermostat housing. Remove the hose clamp and hose (when vehicle is cool). remove the housing itself and the thermostat will be right in front of you. .

You may have a short in your wiring and it may cause more damage by touching any metal surface depending were the routing of the wires run through because the whole car is negative therefore I suggest you take it to an expert electronics technician right away for and electronic diagnostic check up!

check ur fuses

They are 6.5 inch, but may require an adapter because they are slightly over sized. BUT, if BOTH rear speakers quit working, that is probably a problem in the RADIO, not the speakers!

The cylinders are numbered 1-6 from front to back, and that the firing order is 1-5-3-6-2-4.

Good luck and thank you for using Fixya

make sure there pluged in if so you need to get new ones