Getting a powered sub for the trunk. Something small: 10 or 12 inches to give some bass to the music. I want to keep the stock look as much as possible. What would be the easiest speaker wire accessible via the trunk to add in a line-out converter? Any quirks I need to be wary of?

 

Did you ever figure out a spot for this or a wiring harness for the head unit?

 

+1; looking to do the same as the OP. Did you ever find the wires...? I just read the instructions from Crutchfield for removing the factory head unit; are you kidding me? While replacing the rear door speakers I will be looking for those speaker wires in the B-pillar/door sill wiring harness...

Has no one identified those wires? It sure seems like it would be a lot easier to tap those wires back there rather than pulling that head unit out of the dashboard.

 

This is the wire harness that will work for the GK. 99.99% sure this will work even with the newer HU. Yeah that means removing the gauge cluster trim, center vents, taking out the HU with the 3 screws, putting this wire harness in line, then pushing the HU back in place reassembling everything

Wire harness:
Now adding a line out converter, you could tap the rear door speaker wires, sorry I do not have the colors. They are right there in the B-Piller to tap once you do figure that out. It would be easy to identify them when you replace the door speakers by looking at the plug wire colors. Its very easy to remove the snap clips holding the door skin on plus two screws.

However if you do the rear speaker, know that the db is less than the front speaker channels. Your line out converter will need to have an active gain to boost the signal to properly drive your sub's preamp.

Hope this helps. Sorry I don't have the info you need.

 

So I'm not an audio guy but I would like a little bass so this PNP solution looks interesting. Can you tell me what that bundle of blue wires would connect to? I'm guessing the other side is where the RCA lines from the amp would plug into right?

 

Thank you for your input. The aim would be not to have to get behind the head unit. I will attempt to find the rear door speaker wires and report back with pics and other relavent info. Regarding the reduced db's to the rear speakers and active gain, I will be running a Rockford PS-300 10" powered sub. As I understand it, the sub has it's own built-in LOC; and between it's adjustments for: gain, x-over point, and bass boost, I should be able to dial it in okay, no?

I believe the blue wire would serve as your amp's turn on lead...

 

Yes and Yes to both points.

 

Sorry haven't had a chance to reply to everyone I haven't found a solution and the one that is referenced at amazon I'd already purchased and tried it didn't fit my headunits wires at all. I was really hoping so. If anyone once else has an easy solution please do share

 

Sorry that it did not work out, can you take a picture of the back of your head unit? Maybe we can visually match up the connector. Good chance too that because its a new 2018 that the adapter may not be available via retail just yet.

 

Not sure if this will scratch your itch, but here is what I did.

 

Did anyone ever figure out the door speaker wire colors?

 

Is the link below not what you are looking for?

 

Unfortunately it is not I have a 2018 fit and apparently it changed wire scheme

 

Interesting... My 2019 rear door speaker wires are blue/pink. 2Rismo2 has a 2015 and his rear speaker wires are blue/pink. Are you sure yours aren't?

If you look at this pic from the passenger side B-pillar of my 2019, you will the blue/pink wires. In the below pic I had already pulled them out of that black plastic wire loom. Also, note that the blue and pink wires are twisted together. When you pull those wires out of the plastic loom that goes into the door, do you not have those blue/pink wires? If no, do you have a pair that are twisted together like the ones in my pic? If you can't ID the wires from the B-pillar, you could pull one of the door panels and a speaker and just check there. The door panel comes off pretty easy.

 

Hot dog that's it I can't believe it. Which one is positive and negative? ImI bout to make my fit go boom boom pow. Also where did everyone hook up the remote wire to?

 

Blue is positive, pink is negative. The sub I used doesn't need a remote turn on so I am not sure, but I will check for one in the morning.

 

Awesome thank you so much. Do I need to splice it in on the left side too? It's one sub, but to my understanding you still need both left and right channels on it. Am I correct on that.