I ran two Kicker 12's for years off the OEM RF system. I pulled power to the amp from the battery, start wire from radio turn on, ground to a bolt holding the seat down, and a line out converter from the wires on the OEM sub. It let me keep everything on the RF system working, and just added subs that I could remove without messing anything up.

I would use a 30A fuse instead of a 60. Less likely to catch anything on fire, cause if you're blowing a 30A fuse you're doing something wrong.

 

Thanks, I'll keep that in mind. Any specific converter you would suggest? I'm looking at something like a high level to RCA adapter (https://urlzs.com/qPeD4), but do you think it would be better to just use a straight adapter or something like (https://urlzs.com/EmtFr) I'm also trying to avoid doing anything with splicing unless it's absolutely necessary.

 

So, after doing some more research about Line Out Converters (LOC), this is what I ended up getting shorturl.at/fquIX . I plan on just going under the driver seat to splice it into the speaker wires going into the factory RF sub to get that signal to the low level RCA and still keep the sub, then run the RCA from the LOC to the amp for signal, and hook up the power supply using shorturl.at/fhnsS . Then just just plug the subs into the amp. Does this seem like it's going to work? If I plug everything in and it does, I'll try to post some pictures of everything.

 

Links aren't working, but that sounds like what I did. Sub needs 4 things: RCA inputs, 12V power, ground, and 12V turn on signal (pulse when you turn the truck on). As long as you have those and it turns on it's good. Make sure you have a good fuse on your 12V power. I had a cheap one and even though it wasn't blown I got intermittent power issues. I may have misunderstood your 60A fuse from the list before. If that's for the 12V power that should be ok. I think I have a 50A, and haven't blown it.

 

So for the 12v turn on signal wire, I've read that there is a violet colored wire to be tapped behind the stereo. I got everything else connected and run through the truck, but i'm still hung up on that one little part because there are 2 violet wires that I could find behind the radio in 2 different harnesses. http://schemaspecial.com/04-nissan-titan-rockford-fosgate-color-wiring-diagram.html this website has the diagram for it (using the "with Navi" diagram) but would you be able to specify which wire to use based on this? also this diagram has the violet amp. on labeled under slot 20. I'm going to go for that one and see what happens!

 

FULL WALK THROUGH: 2004 Nissan Titan with Rockford Fosgate Stock Audio and Navigation. (Keeping the stock amp and subwoofer under the driver seat) This is just my version of everything I did to hopefully condense all the somewhat contradictory info and methods i've seen out there. I installed a JL audio JX250 amp, with 2 x 12' Kicker CompS subs in a non-ported downfire box under the rear seats in my king cab Titan.


Materials: 8 gauge ground and power wire, 16 gauge speaker wire, 18 gauge 12v remote wire, RCA cable, wire stripper, 5 x tap splice clips, electrical tape, flat head & philips head screwdriver, allen wrench for the amp and fuse, socket wrench.

Alright, I got everything hooked up and it all works! bass sounds great and there isn't any feedback or distortion that I can detect, so splicing the Line Out Converter into the stock sub wire harness is a good and easy option. This changes the speaker level input into RCA low level inputs to get a signal to the amplifier (JL audio JX250 amp in this case).

Step 1) For the LOC: I didn't want to deal with the wire harnesses under the seat so I just tilted it back (1) and it stayed pretty well. Then I removed the 3 screws holding the stock sub in to access the wire harness (2). I used a PAC SNI-35 Variable LOC ($9.65 on ebay)(3) to splice into the sub wire harness using tap-splice clips (vampire clip, scotch lock, etc). Using 4 clips, I attached both of the positive wires from the LOC (Grey & White) into the solid brown wire of the sub harness using 2 clips, and I attached both negative LOC wires (Grey/black & white/black) to the Brown/white wire of the sub harness. Tape it up, plug the harness in as well as the RCA cable, screw the sub back in, I just tucked the LOC around the front of the sub where it seems pretty secure, then screwed the seat back down and I'm good to go with that. The RCA cables will be pointing to the rear of the truck, and the tuning dials of the LOC will be facing towards the front of the seat if you need to access them.

Step 2) For the power cable: I used a 17', 8 gauge cable with a 60 Amp in line fuse (put the fuse in about 8-12 in. from the battery terminal connector because there is a good place to mount it with zipties on a bracket connected to the brake fluid resevoir). then I ran the line towards the front around the battery, then down to the left side (looking from front) of the engine bay into the right front wheel well. I learned my titan doesn't have a covering for this wheel well which was very convenient, but if yours does, the clips holding it in place are fragile, so get more before hand if you want to keep it around. There are a couple more brackets with holes on the top of the wheel well to secure the power cable with more zip ties. I then ran it through a hole in the firewall for what I believe is the antenna wire, it's a bit of a tight fit, but that ends up perfectly on the right of the passenger footwell very close to the plastic piece between the floor and glovebox (4) tuck that in as best you can. I then just popped up the plastic pieces between the carpeting and the door all the way to the back, and tucked the wire into that space which fit nicely (5)(6) all the way back to the rear seats. Boom. Done. Leave the plastic off to hide the amp 12v signal on wire too.

Step 3) For the 12v Signal On (I don't know if this is 100% correct, if you know what to do, please look at the pictures and make sure I did it right)!
Remove the faceplate of the stereo (pannel with all the buttons). Just use a flathead and start at the top part and work your way around to get the clips undone. Pull that off as far as you can and get it to the side so you can access the 4 philips head screws holding the stereo in. Take that out and take out all the wire harnesses, and there were a several violet colored cables. I couldn't find which violet wire to tap into online, so I used these diagrams (7)(8) and tapped into the violet wire in slot 20 with a vampire clip. (9)(10) This was the violet wire that is 5 slots up from the bottom when looking pic 10. I used an 18 gauge blue wire for this, and ran it down through the dashboard which came out again on the passenger side footwell near the center foot air vent (11). I tucked this around to the far right side and then took the same path as the power cable to the back seats. Put the plastic covers back over the wires and then that part is good to go. When replacing the stereo, remember to plug everything back in (I forgot the antenna wire plug). Replace the screws for the stereo, if you drop one in the dash, they will probably fall where you can reach them if you pull back the plastic siding of the footwells on either side. Pop the faceplate back in and that's done.

Connect all the wires to the amp, make sure your grounding wire is in a good place (I attached mine to the bolt holding down the rear seat as it was close to the amp using another 8 gauge wire). You should be good to go after that!

I am still questioning the placement of the 12v remote signal wire since the little power light on the amp stays on when the car is off, but i'm not sure if it's still fully powered on. I guess i'll find out tomorrow whether or not my battery is dead, if not, I'll edit this to remove all doubt, but as it stands, the subs are working great, the truck starts, and nothing burst into flames or shorted out! Again, if you have any better info on the questionable wire, please let me know, but I hope the rest of this is specific enough with pics in the right order and will be helpful for anyone else trying this out.

 

FULL WALK THROUGH: 2004 Nissan Titan with Rockford Fosgate Stock Audio and Navigation. (Keeping the stock amp and subwoofer under the driver seat) This is just my version of everything I did to hopefully condense all the somewhat contradictory info and methods i've seen out there. I installed a JL audio JX250 amp, with 2 x 12' Kicker CompS subs in a non-ported downfire box under the rear seats in my king cab Titan.


Materials: 8 gauge ground and power wire, 16 gauge speaker wire, 18 gauge 12v remote wire, RCA cable, wire stripper, 5 x tap splice clips, electrical tape, flat head & philips head screwdriver, allen wrench for the amp and fuse, socket wrench.

Alright, I got everything hooked up and it all works! bass sounds great and there isn't any feedback or distortion that I can detect, so splicing the Line Out Converter into the stock sub wire harness is a good and easy option. This changes the speaker level input into RCA low level inputs to get a signal to the amplifier (JL audio JX250 amp in this case).

Step 1) For the LOC: I didn't want to deal with the wire harnesses under the seat so I just tilted it back (1) and it stayed pretty well. Then I removed the 3 screws holding the stock sub in to access the wire harness (2). I used a PAC SNI-35 Variable LOC ($9.65 on ebay)(3) to splice into the sub wire harness using tap-splice clips (vampire clip, scotch lock, etc). Using 4 clips, I attached both of the positive wires from the LOC (Grey & White) into the solid brown wire of the sub harness using 2 clips, and I attached both negative LOC wires (Grey/black & white/black) to the Brown/white wire of the sub harness. Tape it up, plug the harness in as well as the RCA cable, screw the sub back in, I just tucked the LOC around the front of the sub where it seems pretty secure, then screwed the seat back down and I'm good to go with that. The RCA cables will be pointing to the rear of the truck, and the tuning dials of the LOC will be facing towards the front of the seat if you need to access them.

Step 2) For the power cable: I used a 17', 8 gauge cable with a 60 Amp in line fuse (put the fuse in about 8-12 in. from the battery terminal connector because there is a good place to mount it with zipties on a bracket connected to the brake fluid resevoir). then I ran the line towards the front around the battery, then down to the left side (looking from front) of the engine bay into the right front wheel well. I learned my titan doesn't have a covering for this wheel well which was very convenient, but if yours does, the clips holding it in place are fragile, so get more before hand if you want to keep it around. There are a couple more brackets with holes on the top of the wheel well to secure the power cable with more zip ties. I then ran it through a hole in the firewall for what I believe is the antenna wire, it's a bit of a tight fit, but that ends up perfectly on the right of the passenger footwell very close to the plastic piece between the floor and glovebox (4) tuck that in as best you can. I then just popped up the plastic pieces between the carpeting and the door all the way to the back, and tucked the wire into that space which fit nicely (5)(6) all the way back to the rear seats. Boom. Done. Leave the plastic off to hide the amp 12v signal on wire too.

Step 3) For the 12v Signal On (I don't know if this is 100% correct, if you know what to do, please look at the pictures and make sure I did it right)!
Remove the faceplate of the stereo (pannel with all the buttons). Just use a flathead and start at the top part and work your way around to get the clips undone. Pull that off as far as you can and get it to the side so you can access the 4 philips head screws holding the stereo in. Take that out and take out all the wire harnesses, and there were a several violet colored cables. I couldn't find which violet wire to tap into online, so I used these diagrams (7)(8) and tapped into the violet wire in slot 20 with a vampire clip. (9)(10) This was the violet wire that is 5 slots up from the bottom when looking pic 10. I used an 18 gauge blue wire for this, and ran it down through the dashboard which came out again on the passenger side footwell near the center foot air vent (11). I tucked this around to the far right side and then took the same path as the power cable to the back seats. Put the plastic covers back over the wires and then that part is good to go. When replacing the stereo, remember to plug everything back in (I forgot the antenna wire plug). Replace the screws for the stereo, if you drop one in the dash, they will probably fall where you can reach them if you pull back the plastic siding of the footwells on either side. Pop the faceplate back in and that's done.

Connect all the wires to the amp, make sure your grounding wire is in a good place (I attached mine to the bolt holding down the rear seat as it was close to the amp using another 8 gauge wire). You should be good to go after that!

I am still questioning the placement of the 12v remote signal wire since the little power light on the amp stays on when the car is off, but i'm not sure if it's still fully powered on. I guess i'll find out tomorrow whether or not my battery is dead, if not, I'll edit this to remove all doubt, but as it stands, the subs are working great, the truck starts, and nothing burst into flames or shorted out! Again, if you have any better info on the questionable wire, please let me know, but I hope the rest of this is specific enough with pics in the right order and will be helpful for anyone else trying this out.

Well, tested everything again this morning, and it's all perfect! So in conclusion, the walk through I gave is a definitive way to get the project done and have it all work. I would like to stress again to be careful with all the parts of your truck. I was a little bit reckless and further trashed my radio face plate, which was already trashed after 15 years of sun in Arizona, so I could stand to get a new one anyways. If anyone has questions regarding this in the future let me know!

 

Glad you got it working. I like the setup keeping the stock sub. It's obviously not as good as a full blown, finely tuned system, but the stock sub seems to take care of the higher frequencies while my extra subs hit hard on the lower frequencies. Pretty sure I connected the amp on to the same wire you did. The easiest way to check would be check voltage with the key out of the ignition. If it's still receiving power find a different wire.