So, here's the deal:

I had a sony headunit in my civic, and i got a del sol, so i swapped the stereos so i could keep the sony in the del sol. I hooked up the pioneer headunit today in the Civic, but it won't power on. The fuse is okay, and the cigarette lighter still has power (it's on the same circuit). I have tried 2 different pioneer headunits on it, and I am 100% positive that the wiring is correct on the stereo. It just won't turn on.

Any ideas to why this might be?

 

Nevermind. I got out the multimeter and found out there was no voltage at the constant power supply. I fixed it.

 

this is the type of thread i like to see

 

Yea, I just don't understand why there was no power at the constant 12V even though it worked perfectly normal before I swapped headunits...


That car didn't have an amp in it anymore, so i just took the 12V wire from the amp wiring kit and ran it to the headunit as a constant power supply. I'm selling the car and I don't have time or patience for stupid stuff like figuring out what was wrong with that wire. It was only getting like .63 volts.

 

the wire you grabbed may have been the signal-switched wire...sends enough voltage to the amp to keep it ready to power up, but won't have 12v until it senses the signal from the headunit

 

With a stock harness, the constant 12V power comes from a fuse under the hood. It's in the fuse box next to the battery and labeled "BACK UP".

You should check that fuse and replace if it is blown because it also supplies the memory in the ECU. Without it, your ECU will have to fine tune itself all over every time you start the car. Also it won't remember trouble codes.