Allow me to clairify if I may.
What DDalder is trying to tell you is this..........Almost every amplifer made for cars needs to have 3 different power wires to work.
1) Main power feed to the amplifer attached to the Positive post of the Battery. This wire should be fused with in 2 feet of the Battery post.
This wire is used to provide the Amp with lots of power because the draw is greater the more you turn the volume up. Typically 8 - 4 gauge is sufficent for most Amplifers.
2) You need to have a good ground to the Amp. This wire should be within 4 feet of the Amp. The ground point should be a solid piece of metal on the body or frame and should be sanded so that it is free of paint.
This wire should also be the same gauge as your main power feed from the Battery.
DO NOT run this wire back to the Negative post of the Battery as the Amplifer needs to be able to dump power as quick as possible.
3) Remote Turn On wire is a small gauge wire (18 g) that Signals the amp to turn on because the Headunit is on.
With most HU there is a wire that sends a Turn on signal to the amplifer if the vehicle has one, or if using an aftermarket HU.
This wire is usually only providing 500mA of power, just enough to tell the amplifer to stay on while the HU is on.
For this wire you can also use a Switched Accessory but the amplifer will stay on as long as the key is in any position other than the Off position.
If you are not using an aftermarket HU then be sure to fuse this wire with no more than a 5 amp fuse.
These are the power wires that are needed to turn on the Amplifer.
Don't forget you still need to get musical signal into the amp. Since you don't have RCA output on a factory HU you will need to tap into the rear speakers for signal or use a line level adapter.
92 Bonneville SSEi - Stock - Remaining repairs needed due to neglect by previous owner - ABS/Trac, AC.
Mods so far: Maganflow High flow Cat, Rebuilt */C
Future Mods: Interior swap for Leath, High Output Altenator, Crazy system, Climate Control swap & Custom Exhaust/Intake.
98 Dodge Stratus - Wifes Daily Driver
92 Dodge Shadow - My Winter Beater