ok heres a question, did a search couldnt find anything:

I had the stock radio in the cobalt, i purchased an aftermarket radio. Now this is from my memory, but I didnt cut into the radio wire harness, i just simply unpluged the wires from the back of the headunit and plugged them into the adapter that was made for the car. That adapter was then plugged into the back of the radio. There was something to do with the factory harness not having a power or something so i had to run a wire from my sunroof fuse to the power wire on the adapter, also a ground.

So i am selling the headunit, i unhook the plugs from the adapter and plug them back into the factory headunit. I have no power? where does the factory headunit get power from? what am i missing?

 

Ttt

 

Someone?

 

did you unhook the car battery before unplugging the headunit?

 

The head unit is probably locked, when you plug in a factory head unit, it locks. (theft ****)

 

^^unless the battery isn't hooked up when taken out and put back in then it doesn't lock.

 

our radios are "locked" to a vin number. as long as your vin number isnt changing (bcm swap maybe idk how you would do that) then battery hooked or not wouldnt matter.

If you didnt cut anything then it should power on by plugging in. i am curious as to why you had to run your own ground. Did you try touching that ground wire to the radio chassis to see if it powers up then?

 

i dont think its locked, im just not getting any power. Didnt do anything to change vin or any of that. Didnt cut anything on the harness, i had to run a ground on the aftermarket headunit, and a 12v source. i think im gonna try to unhook my battery, let the car sit for some time then plug it back up. see if that does anything

 

You said you had to tap into the sunroof for power am I correct? If so check all the fuses, and I mean all of them, could be a blown fuse, common ones to check are cig lighter, dome light, and radio and or audio fuses

 

A blown fuse, even one that has nothing to do with the radio, could make it so my radio doesnt have power? doesnt seem right, ill check tho. I have my radar tapped in on the same fuse that i had the radio on, the radar works fine.

 

why did you have to run a ground to the aftermarket radio? if yoyu utlized a harness to go to the stock harness it would have the speaker wires ground and constant power. you should have only needed to run acc.

If for whatever reason the stock ground is disconnected the stock radio wont work.

The issue you have is its not turning on. all you need to fix that is ensuring the 12v constant works and the ground works. Then the radio should turn on with GM LAN. if for whatever reason the GM LAN data is busted then you might as well go back to aftermarket

 

Yea constant or 12v can come from a couple if different places the ignition or "remote" power usually comes from the fuse labeled radio. What makes me think it's a fuse is the fact that you had to get power from another source, in this case the sun roof.

 

you should never have to run acc power, you're supposed to use the module that's correct for the car pac and metra make them I know idatalink also sell the correct ones for our cars

 

right. the only reason you would need to run acc is if you didnt get the module harness. but if you have the module harness you shouldnt be running any wires anywhere other than the harness. since the OP posted he ran 12v and ground i would hope hes wasnt using the module harness

 

That's why I think it's a fuse because the factory harness supplies all the necessary power to the stock h/u