what is the voltage of remote turn on

I believe I have an issue with the turn-on signal wire from my head unit to the amps. It seems to be an internal short - like a cold solder - so what I'm thinking of doing for a short term fix is to connect the remote wire to a relay (?!) and just have the amps come on with the ignition. The amps are on 99% of the time the car is running anyways. Is this doable and if so, what is the common voltage to turn on the amps. I have searched and found nothing to answer this, so if its been covered, please just refer me to the link and forgive the repost. Thanks.

Depending on the vehicle, you may not even need a relay.  Simply connecting the remote wire to the ignition feed will work just fine.  The remote wire is the same exact voltage as the ignition feed. 

What kind of radio do you have?   How many amps and signal proessors are you turning on with the remote wire?

You probably pinched the remote wire or drilled into it. Check for continuity to ground on the wire.

I have a Sony (Japanese model....weighs about 3x as much as the junk sold in the US). Its running 2 Harmon Kardon amps. The wire is untouched - I ran conduit front to back - strap/clamped down - nothing is drilled or crimped. I already checked it for continuity and all connections to the head unit. When its cold, the amps just don't come on. Once the car is warmed up, they work great.....and this didn't start until it got really cold out. If I can really just tap into the ignition wire, that'd be great.

I should add the radio is about 7 years old and this is the 3rd car I've had it installed in, so its not exactly 'new'. Its a very custom install with the climate controls moved, etc. - so I really dont want to tear things apart if I can bypass the HU and turn the amps on directly. The wiring behind the HU is actually quite accessible.

yes you can connect the remote wire to the red wire of the radio.

Conduit from back to front! LOL! Now why didn't i ever think of that! commit your way to jehovah and he will act in your behalf. psalms 37:5

I should have said "loom" instead of conduit. Its held down through routing with the OE harnesses and an occasional strap/screw (which doesn't go through the loom of course). Sounded like I drive a nuclear sub or something....lol. Thanks very much guys!

measure voltage in the remote line (blue) of the radio,  it should be 12volt or try with test light. if it's right the throuble is in the remote line , then remplace it.

UPDATE: turns out it wasn't the head unit or the wire - I think its the amp. I jumpered the remote line onto the ignition 12v, and it worked perfectly....for about 10 minutes, then the amp shut off again. I used a DVOM and checked voltage at the amp, both from the battery and the remote - both had 12v. When this issue started, the amp would kick off in a hard turn or after a bump. Sometimes after another bump, it would come back, but then it progressively got to the point of not coming back on after shutting off. I'm thinking a cold solder perhaps? Maybe a loose connection internally? The roads where I live are gawd-awful so the beating everything in the car gets is ridiculous. Its a Harmon Kardon amp - about 6 years old. I'm going to be pulling it in the next day or so to see if there's anything obvious. The car is tentatively sold, so I dont want to replace it, but want to fix it right. I lost enough money on the deal.