The deck has to be a aftermarket deck. On the wiring harness, you will see a blue wire that says rem. Hook it up there and you should be good
the remote wire goes into the back of the deck (head unit). it tells the amp to turn on when the deck is powered up, if you don't connect it it will continue to drain power from your battery.
You only need the remote wire if you have an external amp.
Amp always on
the rem slot on your amp to the rem trigger on your deck (blue wire on most aftermarket desks)
when connecting an amp to your car before you put your dash back together there will be a wire on the back of the stereo that will say remote an that's where you connect it then after all that's down get the song "Broadway" by spm
Run your power, ground, and remote wires. Then connect your RCAs to the back of your CD player and your amp, then connect your speakers to the amp..-Shocker
Okay first of all I have to assume that you've added an Amp and Sub to to the vehicle and that the only thing stock is the deck. The reason the Sub's amp is only working when the radio is on is because the remote wire on the Amp is connected to the power antenna wire on the deck. The deck only powers the power antenna when the radio is on then turns it off when you switch to CD because the antenna isn't needed to play a CD. If the deck also has a wire labeled remote then use that one instead. If there is no remote wire on your deck an alternate solution would be to connect the remote wire on the amp to a (switched hot) or acc fuse in the fusebox (in other words to something that is only powered when the key switch is on like the windshield wipers, if you connect it to something powered all the time like the lights or horn then the amp would stay on all the time and kill your battery) this way the amp will be activated anytime the Key switch is on and would work regardless of whether you are listening to the radio or playing a CD.
Easy way to check were the problem is take a 6" piece of wire. Unhook the remote wire from your amp. Then hookup your 6" piece of wire to amp remote terminal then take other end and connect to the 12+ terminal. If amp powers up the its in the headunit. If amp does not powerup or goes into protect mode the amp is problem.
What it is, is your power ant. wire is hooked to your remote(control) wire of the Amp.To fix this disconnect it and connect it to the remote(control) wire. If you dont have a output labeled as this connect it to the hot wire for the radio. (do not connect it the the constant hot wire there will be two different wires)
It runs from your deck to the amplifier. When the deck turns on, it sends a low voltage signal to the amp to let the amp know to turn on. If you are running an amp on a stock stereo, there are other ways to turn the amp on without a remote wire, but that's the easiest way. So, simple answer, it turns your amp on when the stereo comes on.
Your amplifier should(hopefully) have an input for a "remote turn on" or some words to that effect. Hopefully your deck has either a "remote turn on" wire or a "power antenna" wire coming out the back of it. If it does, you're in business. Extend it to the "remote turn on" on the amp and you should be good!
if you are talking about an aftermarket radio's amp turn on wire then without an amp you can just cap it off. if the harness used to connect to new radio to your factory wires has a blue antenna/factory amp then you can connect it to that provided the new radio doesnt have a second blue wire for that purpose.