The white factory amp turn on wire should be used. The head unit provides current for that. You want both short circuit and over current protection for the head unit.

Don't use ignition wires for amp turn on. It will cause the amp to turn on before the head unit, which will result in pops and noise that can damage the speaker/sub.

Also, I fuse any factory +12V wire I tap for car audio purposes. The remote wire is always subject to damage or short, and you don't want your ignition fuse to ever blow. If you do need to tap a factory +12V wire the proper way is to use a fuse tap so the wire has proper protection at the fuse box and the factory fuse is independent. And always take care to consider the additional load and what is upstream of that tap. When I need more than 5A I will use a relay and run a wire to the battery. The battery provides the current, the factory wiring controls the relay coil.

In the past 20 years I have seen a lot of damaged gear and vehicle wiring due to improper wire taps and inadequate protection. I have seen a lot of damaged speakers and subs from ignition turn on due to the amp being on before the head unit. High quality amps can have internal delay features to protect them. Cheaper amps may not. I always take the safe route so my customers don't come back with problems. I give advice on the forums the same as I would do in my own garage, fool proof reliability and safety.

I don't like to correct people when I comes to personal opinions, getting opinions is why forums are useful. But I will comment and control advice that, in my professional opinion, compromises the safety of the vehicle or it's occupants. If I recommend fusing, it's best to follow my advice.

 

i think that answered my question. I think. So what you are saying is that any thing added before the power gets to whatever it is powering puts an additional draw on anything else run from that same wire? if so, then i understand why you would fuse.

i completely agree about not having the amp turn on before the head unit i just didnt see that other wire and did not see anything else to tap.

My biggest question is I dont quite understand completely how it hurts the head unit if the my understanding of what i quoted is wrong. I wasnt trying to correct you. that was a sincere question about something that i dont understand.

 

No problem man, I understand your point that tapping the purple wire does not endanger the head unit, that I agree. However, you would still fuse the purple wire tap, at 0.5A or 1A when using it as a remote turn on. A remote wire can be 18awg, typically blue in color. Whenever tapping a wire with a smaller gauge wire, you fuse the smaller gauge wire since the fuse protecting the larger wire is too big to protect the smaller wire. Additionally, a remote turn on draws a couple hundred milli-amps. As such the 0.5A fuse protects the amp incase an internal issue causes a problem. If you had a 20A fuse protecting the remote wire, and the amp had a problem, you would destroy the amp circuitry before the fuse blew. With a 0.5A fuse, the amp could be repaired.

Here are the reasons for fuses:
1. Short circuit protection for the source. Located at the source.
2. Over current protection for the wire. Located at the source or load.
3. Over current protection for the load. Located at the source or load.

All three should be met at all times. So when considering if you should or should not fuse, verify that these are satisfied.

Lastly, when cascading fuses, we size them such that a problem doesn't blow all fuses, just the first fuse. We coordinate this with sizing. If we have a 10A fuse then another 10A fuse down the line, a short at the end will blow both. If we have a 10A fuse and a 5A fuse, we hope the 5A will pop and the 10A will remain ok. Keep in mind that a fuse lets 300% of its rating through before it blows. For more on that, look up time-current curves for fuses.


If a LOC with turn on is desired, I recommend this one:
Products

 

ok so i ran the wires today and had some issues with the pinset diagram. The white wire was a 14v constant it stayed on regardless of key in or out or radio on or off. However the purple wire had a 14 v current to it when the radio was on and off but read 0 volts when the car was turned off and key was out. I got chased into house tonight by mosquito's so i was unable to splice the wire, what do you guys think sounds like the wire i want, it tested other wires in hopes i would come across a wire that only sent a current when the radio was turned on but no luck with this factory radio harness. Is this right that the remote wire sends a 14 volt CONSTANT signal when on to the amp to open a relay? keep me posted tommorow morning i hope to knock this out

 

also this info from that diagram posted earlier does not exist Factory Amp Turn-on white + radio, gray 24 pin plug, pin 17, this pin is empty just a plastic hole no wire.

 

The pin exists on the head unit, and it is the pin you want. Simply get a Molex pin and insert it into the harness with your own wire.

 

Well hooked it up and man am i SADLY disappointed.not sure what to do.

I was in a park trying to tune it and its was very difficult.

Equipment was boston acoustic 400m 250w @ 4 ohm and kicker substation 80.

1. Ok first of all i am using the high level inputs off the rear speakers and i used regular speaker wire to hook it to the harness of the amp

2. Its very difficult to set bass in car as the bass dial affects all the speakers and not just the sub so everything distorts.

3. when i had this speaker running with an hcaa 225 orion amp that thing slammed so hard, but i had an after market headunit and eq, unlike now me trying to run it off a factory head unit.

i am debating buying this GTA_RSL remote wire that plugs into amp that allows you to just adjust the bass without messing with the radio controls.

Here;s some weird stuff that i noticed. I started to drive out of park and for a brief 5 sec the bass got really loud like when the car was driving more power was getting to amp or something, then stopped. a few blocks later when i was coming to a stop i swear i heard the downshifting effect through my sub for a sec. I was not able to recreate them however.

The amp turns on with ignition for now, and shuts down properly, the power reads 14 v and when i check ground its great too.

Only 2 wires from rear speakers are pressing through the same hole power ground and remote are, maybe there is some cross communication?

is it ok to have power and ground wire close?
I should keep power/ground wires away from speaker input wires?

 

Driving around i now get a very loud rumble from sub approx every 30 to 60 sec, its a double pulse of bass that just hums and then stops, it does not sound like alternator noise its a double pulse of really loud vibration and then stops.

The amp had a high level input pin on it, it has 4 wires left/right, + and -, so i hooked both rear speaker to this input, was i only suppose to hook up one side? could this be noise coming from having 2 speakers going to amp and now amplyfing some type of engine noise?

 

you should have both rears hooked in. your wine is probably coming from your power being run with the rcas. the poppoing or random bass is probably a bad ground.

 

well it turns out that i disconnected the ANC mic's and all is well, those buggers where trying to counter act the bass and where sending all sorts of signals to the speakers and sub. car works perfect now and im thumping away. So i take it back you can have a factory radio and add a sub and have it sound great. Just need to dial in amp settings. I am currently down to 100hz low pass which sounds good anything over speaker distorts and gain is approx 3/4 up.