2010 Factory Nav/sync aftermarket system

First off, im going to say that i am no expert at all when it comes to stereo's which may be quite obvious. I have a 2010 with factory nav/sync headunit and i tried running an aftermarket amp/sub combo. Basically, i used an rca converter and tapped into the factory sub harness so that my amp could get the right frequencies. After installing this set up, i was a little upset on how loud the subs were so i figured it was something to do with the RCA converter. This weekend, i took the dash apart and behind the headunit i found a set of rca cords that were coming from the headunit and ran into a harness. when i plugged the rca cables running from my amp, to the cables from the head unit i would get no bass, but if i ran adapters from the headunit so that i could use the cables from the amp, and cables running to the factory harness, the subs would hit HARD like i assumed they should. But, the bass would not adjust with the volume on the head unit and it would stay at the same level the entire time unless adjusting the gain on the amp. Also, if i went to the "radio" on the factory headunit it would play no bass. So basically only bass was coming from my bluetooth device or the sync. I assume the rcas coming from the headunit have something to with the sync hence why they play with my sync device.

Not sure if i can be helped out here without having someone look at the system in person but i figured it was worth a shot.

If there arent any answers, how do you guys have your systems wired up with the factory nav head unit? Im curious to hear what works for you guys. Thanks a ton!!

I'll admit that factory integration stuff is a bit over my level as I am just an enthusiast and don't have a shop or access to play around with the new stuff, but here are my thoughts...


I think with these factory amped systems you get VERY very low voltages in the wires leading to the amplifier (factory sub harness) a powered RCA converter might be able to help on this, as it would be able to boost the factory signal before it gets sent to the amp.


I would try splicing the RCA converter into a standard speaker wire and see if that gets you a solid audio signal. Then you can cut out the high notes by adding a low pass filter (should be a dial on your amplifier) at around 100hz.

Ahh that does make sense. I'm gonna try that out for sure. What's the easiest way to tap into the speaker wire? T-taps? I just cut and spliced the factory sub/amp harness bc I wasn't gonna use it again

Yea T-taps will be the easiest way.