amp turn-on wire no output on headunit

I'm installing a generic (Chinese) dvd/gps headunit into a friend's 2012 Kia Sedona. I got the Metra harness kit, however the headunit does not have an amp turn-on output to connect to the Metra harness... Is there any other way this wire can be powered? And is it just a 12v positive signal? The single-wire orange connector in the pic is the one w/ amp turn-on wire. At the moment I have left it out but I can't tell if it's effecting the sound quality. Any harm in the amp not being on during audio playback in the mean time? Also, is an interface module required for the steering mount volume control? if I recall, the headunit has a "key 1", "key 2", and a couple of "CAN" wires (I beilieve CAN 1 & CAN 2) that aren't being used.

Connect the amp turn on wire from the vehicle or your aftermarket amplifier to the same place the Radio's red wire is connected. This will turn your amp on when the key is turned on. But if the remote wire of your radio is dead, this is your best option.

Hmm, so in that case the amp would be powered at all time while the vehicle is running..? Sounds like that could shorten the life of the factory amp... I think I'll just leave it unpowered if it's not harmful. The sound didn't seem bad but I'm really bad at judging sound quality (not much of a sound guy, I like it quiet).

if all of your speakers work without the remote wire hooked up then it is not needed. it is probably only in the harness because on a different model or trim level it is there, so they make the harnesses as universal as possible without having to make a special harness for each trim level .

That makes sense, good news to me too! So you think if it did have a factory amp, the speakers would not work (or the sound would be noticeably horrible)? Thanks for the answer btw.