landon1992

Hello I'm Landon,

Anyways I have a 2004 F150 lariat 4x4 full cab, and was wandering when installing an external 4 channel amp, do the speaker wires from the speakers (all 4 of them) actually go directly to the amp or do you hook the speakers up to the factory wires like you didn't have an amplifier and were just replacing the OEM speakers with aftermarket speakers. So basically my question is where exactly do the wires from your aftermarket speakers input into the amp, from behind the head unit or from the speakers directly? Thanks.

I understand how to wire a single subwoofer system I am just a super noob when it comes to anything greater then 1 speaker.

On another note I have looked through a lot of threads on this website so sorry if I missed a thread that has already answered this.

landon1992

I was just sitting here thinking, in a single subwoofer setup you hook the subwoofer wires directly to the amp, then you have your rca + system power wires going to the head unit, so i guess it's the same thing with the aftermarket speakers then? You run all 4 speaker wires to the amp, and then you have two sets of rcas coming from the headunit + the system power wire? Am I correct?

Thanks

jbone14

Your on the right track. First you send an audio signal to the amplifier, whether it be speaker level (speaker output from back of factory headunit) or line level (rca outputs from an aftermarket HU). When you have an input signal to the amp as well as your power ground and remote you will then output the amplified signal via speaker wire to the speakers. You can do this several different ways, you can physically run new speaker wire from the amplifier to the speaker locations or you can use the factory speaker wires that are already existing. The F150 is great for this as you can purchase a headunit harness from Metra that allows you to cut it in half and 1 side becomes your audio signal to the amplifier, and the other becomes your speaker wire runs to the factory locations.

landon1992

Okay I think I understand now. Although I'm a little confused on the Metra Harness, I have never personally installed a aftermarket HU so this will be my first attempt. I understand I need a metra 70 5520 as I do not have the audiophile system. But when you say cut it in half and one side will be audio signal and the other will go to factory locations I'm confused on.

Thanks.

Edit: Actually I remember watching that guys video on here about that today I'll have another look

Edit: When you say cut it in half are you referring to the 2 harnesses that comes with the 5570 harness kit (the 24 wire, and the 8 wire plugs) + the 16 way plug for auxiliary/charger

Edit: macaboo posted a install video on the harness kit and I understand now what you mean when you say cut it in half i believe.

https://www.f150forum.com/f30/diy-vi...art-one-82376/ -- thats his video.