Hey so im a newbie at wiring this is my first car stereo iv ever wired. But i have a sony cdx-gt09 I got it from a friend so i dont know if its broken or just user error.
But iv connected the power wires together so i can hear it turn on but the screen doesnt turn on. Iv tried wiring speakers to it and see if it plays a cd but nothing happens when i put the cd in. Iv tested the wires with a 12v test light. And my power wires seem and ground wire seems like they are all hooked up they all get a signal with the light. but when iv tried testing my speaker wires nothing comes up. So can anyone help me out?

 

you have enough power? aftermarket HU's alot of times require bigger wires than stock. try hooking it directly to the battery. ground has to be as big as power too.

 

You connected the 12 volt constant. How about the 12 volt switched? Is that also connected? How did you connect to the factory harness? Harness adapter or splicing the factory wires? Oh so many questions, but I've been there buddy. Granted it was like 16 years ago when I was first messing with car stereos but I do feel your pain.