Planning Dual 12" Rockville Install: Can I bypass Bose "Bass Choke" without a full rewire?

[Joseph Garcia]

The reality is that you can use a single quality 10" sub in an enclosure specifically designed for it with a 500W RMS amp, and have clean and powerful low sounds that are compatible and blend in with the rest of your speakers. You really don't need more than that, unless you are into setting off car alarms in the parking lot or wanting your neighbors to hear you coming, when you are 2 blocks or more away from your house.

That is what years of experience will teach you. At one time in the past, I had a custom designed speaker enclosure with so many speakers and amps in the thousands of watts that it took 3 people to load it into the vehicle. Now, I'm happy with my custom matched 10" sub and enclosure powered by 500 RMS watts. I learned.

 

[Doubeleive]

View attachment 484458

you might want to invest in some grill covers for those speakers, there usually not very expensive depending....
all it takes is for something loaded in the back to rub against it or cut the surround and then it's game over.

 

[iboughtatahoe23]

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Trying to figure out what is positive and negative on the factory sub harness ? There’s four wires?

 

[Doubeleive]

Trying to figure out what is positive and negative on the factory sub harness ? There’s four wires?

you can check the charm li manual, but you'll probably want to note the amp p/n or bose system number which will be in your rpo codes like UQA, UQS, Y91, UC6, UB0

 

[iboughtatahoe23]

Hey guys, just wanted to give a quick update for everyone.


I ended up scrapping the Rockville dual 12s and went with the CT Sounds Tropo dual 10” package + their monoblock amp instead. Still keeping the factory Bose head unit (non-touchscreen) and no full rewire — exactly like we were all talking about.


Last time I tapped the factory sub harness (the 16-pin one under the center console cup holders) straight high-level into the amp and it had that same choked/weak/rolled-off bass everyone warned about. This time I’m doing it the right way: tapping the same sub harness wires into the high-level inputs on the CT Sounds LC2i line converter (the CT brand bass restore version Doubeleive mentioned), then running clean RCAs from the LC2i into the new amp. Hoping the bass restoration finally cleans it up.


I’m in the middle of the install right now and have a couple quick questions for you guys who’ve done these 07-14 Tahoes:


1. Ground — I’m using the factory chassis ground stud in the driver-side kick panel/fuse box area (silver bolt with the blue wire and white ring terminal). Is this a solid/reliable spot for the amp ground, or is there a better one up front that doesn’t involve drilling to the frame? I’m about to clean it up real good.


2. Remote turn-on — Best fuse to tap in the driver-side fuse box so the amp and subs turn off cleanly with the key (no drain)? I keep seeing the SEO/RAP fuse mentioned — still the go-to?


3. Sub harness wire colors — Can anyone confirm the exact + and – on these four wires I’m tapping for the LC2i?


• Dark Green


• Dark Blue with White stripe


• Light Blue with Black stripe


• Light Green with Black stripe
(I know + to + and – to – but want to be 100% before I cut.)


Pics of the ground stud and the sub harness attached if anyone wants to double-check.

 

[iboughtatahoe23]

you can check the charm li manual, but you'll probably want to note the amp p/n or bose system number which will be in your rpo codes like UQA, UQS, Y91, UC6, UB0

I’m not 100% sure on my exact RPO codes yet (will grab the glove box sticker on my lunch break around noon or sooner), but my truck is a non-touchscreen 2007-2014 Tahoe with the factory Bose system. I have the four wires on the sub harness under the center console:


• Dark Green


• Dark Blue with White stripe


• Light Blue with Black stripe


• Light Green with Black stripe


I’m tapping these into the high-level inputs on the CT Sounds LC2i (then RCA out to the new monoblock). Last time I went straight high-level to the amp and it was choked/rolled off like everyone described.


Any chance those colors line up with a common UQA/UQS setup on these trucks, or should I definitely pull the RPO codes first before I cut? I’ll post the codes as soon as I check.


Thanks again man — this thread has been gold.

 

[Doubeleive]

Don't trust me on this, it's what AI say's which I trust about as much as a 1000lb gorilla
but if you find similar data then it could be

Wire Color	Signal Description	Pin Type
Dark Green	Subwoofer Signal (+)	Positive
Dark Blue / White	Subwoofer Signal (–)	Negative
Light Blue / Black	Subwoofer Signal (+)	Positive (Alternate/Second Coil)
Light Green / Black	Subwoofer Signal (–)	Negative (Alternate/Second Coil)

 

[iboughtatahoe23]

Don't trust me on this, it's what AI say's which I trust about as much as a 1000lb gorilla
but if you find similar data then it could be

Wire Color	Signal Description	Pin Type
Dark Green	Subwoofer Signal (+)	Positive
Dark Blue / White	Subwoofer Signal (–)	Negative
Light Blue / Black	Subwoofer Signal (+)	Positive (Alternate/Second Coil)
Light Green / Black	Subwoofer Signal (–)	Negative (Alternate/Second Coil)

Thanks I’ve also been consulting with AI lol. Also here’s those codes?

 

[iboughtatahoe23]

 

[Doubeleive]

View attachment 485177

the gm upfitter guide should have the wiring diagrams for UQA under gmt900

 

[iboughtatahoe23]

Quick update for everyone — especially Doubeleive, thanks again for the RPO code tip!


Confirmed UQA on the glovebox sticker. Tapped all four factory sub harness wires into the CT Sounds LC2 high-level inputs, ran fresh speaker wire, solid ground on the driver seat bolt, and power/ground is done.


Houston, we have bass.


Fired it up and it’s already slamming way harder and cleaner than my old straight high-level setup ever did. The LC2 BassLift is working great — barely even touched the knobs and it thumps. I haven’t messed with the amp too much yet (still at work), but I turned the LPF up a bit and bumped the gain just a hair. Overall it sounds pretty damn good, but the higher bass notes (kick drums and stuff in the 45-70 Hz range) are still coming through a little weak compared to the really low end. Planning to dial in the subsonic and fine-tune the rest when I get home.


Only thing left is the remote turn-on wire so the amp + LC2 shut off cleanly with the key (right now it’s on constant 12V). Is fuse #8 (SEO / RAP) in the driver-side dash fuse box still the go-to for these 07-14 UQA Tahoes? Any tips on the best add-a-circuit setup?


Once I’m home and finish dialing it in I’ll post final settings and maybe a quick clip. This CT Sounds Tropo dual 10” package is already legit


Thanks again!

 

[Doubeleive]

Quick update for everyone — especially Doubeleive, thanks again for the RPO code tip!


Confirmed UQA on the glovebox sticker. Tapped all four factory sub harness wires into the CT Sounds LC2 high-level inputs, ran fresh speaker wire, solid ground on the driver seat bolt, and power/ground is done.


Houston, we have bass.


Fired it up and it’s already slamming way harder and cleaner than my old straight high-level setup ever did. The LC2 BassLift is working great — barely even touched the knobs and it thumps. I haven’t messed with the amp too much yet (still at work), but I turned the LPF up a bit and bumped the gain just a hair. Overall it sounds pretty damn good, but the higher bass notes (kick drums and stuff in the 45-70 Hz range) are still coming through a little weak compared to the really low end. Planning to dial in the subsonic and fine-tune the rest when I get home.


Only thing left is the remote turn-on wire so the amp + LC2 shut off cleanly with the key (right now it’s on constant 12V). Is fuse #8 (SEO / RAP) in the driver-side dash fuse box still the go-to for these 07-14 UQA Tahoes? Any tips on the best add-a-circuit setup?


Once I’m home and finish dialing it in I’ll post final settings and maybe a quick clip. This CT Sounds Tropo dual 10” package is already legit


Thanks again!

should be a yellow wire on connector x14 (mbec) pin 8 maybe, apparently it can vary based on the vehicle model. the rap is controlled by a relay, the wire is low power for trigger-on use only. be careful because you can mess up the vehicle lan buss if you connect to the wrong wire

 

[iboughtatahoe23]

should be a yellow wire on connector x14 (mbec) pin 8 maybe, apparently it can vary based on the vehicle model. the rap is controlled by a relay, the wire is low power for trigger-on use only. be careful because you can mess up the vehicle lan buss if you connect to the wrong wire

I tested the AUX PWR fuses (#2 and #16) and they’re both constant-hot (even with door closed and key out). My dash cam stays on them too.


Would it be safer/easier to just tap the accessory wire at the factory radio harness instead of hunting for the yellow wire on X14 pin 8? Or is X14 still the cleaner way?


I’m trying to keep everything stock-looking and not mess with the LAN bus like you warned. Any quick confirmation on which wire/color at the radio is the switched accessory one on a non-touchscreen UQA setup?


Thanks again!

 

[iboughtatahoe23]

On second thought, the factory radio does not have a traditional accessory wire I read — it’s all controlled over the data bus (GMLAN). Tapping the radio harness won’t give me a simple 12V switched signal, so it’s not the easiest option here.

 

[Doubeleive]

On second thought, the factory radio does not have a traditional accessory wire I read — it’s all controlled over the data bus (GMLAN). Tapping the radio harness won’t give me a simple 12V switched signal, so it’s not the easiest option here.

you should be able to tap the wire in the mbec mid buss electrical panel, it's the panel that has a black plastic cover on it to the left of the brake pedal sort of on the firewall

 

[Fless]

The MBEC has been mentioned several times now in this thread and your others. It has connections for exactly this purpose.

Fuse tap

What fuse at the dash near the passenger door can I tap that only comes on with the ignition so far I haven’t had any luck with any of them so my amp to my subs is always on unless it’s unplugged.

www.tahoeyukonforum.com

 

[iboughtatahoe23]

The MBEC has been mentioned several times now in this thread and your others. It has connections for exactly this purpose.

Fuse tap

What fuse at the dash near the passenger door can I tap that only comes on with the ignition so far I haven’t had any luck with any of them so my amp to my subs is always on unless it’s unplugged.

www.tahoeyukonforum.com

Sorry. First I had to get the dang things hooked up and actually working

 

[iboughtatahoe23]

you should be able to tap the wire in the mbec mid buss electrical panel, it's the panel that has a black plastic cover on it to the left of the brake pedal sort of on the firewall

Pin 8 on X14? So I can just take a self adjusting wire stripper and open a section up? Or what’s the best way to tap that? Wire T taps have been unreliable for me in the past. Also don’t wanna sever any wire

 

[Doubeleive]

Pin 8 on X14? So I can just take a self adjusting wire stripper and open a section up? Or what’s the best way to tap that? Wire T taps have been unreliable for me in the past. Also don’t wanna sever any wire

I usually use one of these female blade power tap's (depending on the wire thickness), that allows you to insert a male blade connector.

 

[iboughtatahoe23]

I usually use one of these female blade power tap's (depending on the wire thickness), that allows you to insert a male blade connector.
View attachment 485266View attachment 485267

Ok those are safe to use on that harness? Those are the ones I have had troubles with in the past. I think it was cause I was using the wrong size though maybe. What size wire is it do you know by chance from when you did it?