80 Rabbit, 04 ZHP, 71 Opel 1900, 87 325i, 14 Cheating Diesel
Make sure you are using the blue/white wire. Some radios also have a blue wire, which is power antenna and only works on am/fm.Stereo update:
End result: My headunit has a amp remote (wake up) line, but it doesn't send a signal down the wire. This means the amp doesn't turn on. Now I have to decide whether to replace the HU or wire the amp to an ignition line. Meaning it will always be on when the engine is running. The car is still in bits until I make up my mind.
As a temporary fix, you can hook up the amp turn on to the red wire, which is keyed power. Likely you will have turn on/off pop though.