Alright...let me try to document out the steps it took to complete the install. I have some pictures to include along the way. You can do this...it's not too hard. Set aside 4-6 hours. Get all of our equipment ready. See my setup below
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Step 1. I"m going to assume you have all the needed hardware, and tools. Make sure you have a 10mm socket handy as it's used in multiple places. Watch the video of the guy doing the install on the Sierra that I posted at the start of this. 3/4 of this video aligns exactly to the 2015 Tahoe...step for step!
Step 2. Pop off battery top cover, located on passenger side under hood. You'll see multiple battery posts, even one that is exposed without a wire running to it. I didn't have a bolt handy to fit it so I connected to the first post, nearest the front. If you purchase the second kit (Boss Audio) you'll need to cut the power cable (about 2.5 - 3 feet from the battery) and install the fuse and the attach the remaining 17ft of power cable. Don't forget to run the wire loom over the wire! It's easier to do so before you have the fuse in-line. See pictures below.
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Zip tie that guy to the wire/loom that's already running along the backside of the engine compartment on over to the far driver side.
Step 3. Cut the little nipple off the rubber boot that you'll see in the picture below. You can use a long screw driver to poke down in the hole to make sure you have a clear path heading down towards the bottom of the inside of the cabin. The picture below is obviously the finished deal....but you'll need to skip to Step 4 to dismantle the inside in order to see/feel the power cable when you start to feed it through the hole you cut in the rubber boot.
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Step 4. Probably the most challenging part of the install....As mentioned previously watch the Sierra install video. The guy does a nice job of showing how to pop the top off the black box near the brake pedal. You goal is to use the 10mm socket to remove this electrical housing, move it aside, and reach up back behind there looking for a round rubber grommet, about 4 inches in 5 inches in diameter . You need to yank that gasket out....it's pretty much worthless as you won't be re-installing it. It will be handy to have a buddy at this point start feeding the power wire through the rubber boot (mentioned in step 3) and you can be feeling for it from the insdie. Pull the power wire through once you can get your hands on it!
Step 5. Now it's time to install your amp turn on wire. You'll be connecting this to a empty pin inside that electrical box you just unbolted. The picture below shows the 3rd pin from the top on the left hand side. In my photo it's slightly bent to the right. This is a fairly small pin, so you may need to pick up a wire-end to connect to it.
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Step 6. Now it's time to start running your power, and amp turn on wire to the rear of the vehicle. You'll pop up the lower running cover from the driver down through the passenger. See the pics below!
View media item 25629View media item 25622There is a nice little groove the cables will fit into. Don't put the covers back yet if the amp you've purchased has an adjustable base knob as you'll need to run this back up front after you have the amp installed in the rear!
Step 7. Here is where you can get a little creative. We choose to mount the amp to the side of the box as you saw a few posts above. Ideally you wan't it somewhere to get SOME airflow as the amp will heat up! I would first remove the storage compartment in the very back. Open it up, there is a removable liner in the bottom of it, and on both sides is a big circle nut looking thing you can hand unscrew. This will now lift out...put it aside. This way you can get to the bottom of the drive side rear panel to run your wires easier. You now need to pull signal off of the factory amp. The factory amp is accessable through the rear fuse panel on the inside back driver side Pop that panel off and then unscrew the tire jack and remove it. Makes it easier to work around...you'll put it back later. Behind that you'll see the factory amp. if I remember correctly the top connector into the amp has the cables you need. Mentioned previously in the post are the colors for the + and - Subwoofer wires. You can see in the picture below they are pulled out behind the screw driver. You may need to trim back some of the factory black wire tape/loom they have.
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You'll need to use a
wire tap connectors to splice you speaker wires into the factor amp out wires mentioned above. These speaker wires will then wire into your line-converter. Since we don't have left/right outputs you'll notice in the picture below they are twisted together. Make sure you get the polarity right (positive to positive..etc)
View media item 25625Your RCA cables will plug into the line-converter and then into the amp. I won't post details about the amp as you may have a different one...follow the manufacturer instructions for the amp! I chose to run the wires down underneath the the back panel. In the picture above you can see the power wire, bass knob wire, and the amp turn on wire. I had NOT ran the amp ground wire yet. I mention it later on. I have yet to hook up the RCA cables, but they ran the same path. You can plug the factory connector back into the amp, double sided tap the line-converter somewhere inside there, put the tire jack back. My line converter had an adjustable knob of which I just have it cranked as I want to adjust the base from the amp. You'll also need to ground the amp. I grounded it to the bottom screw of the factory amp that you can see just below where the car jack screwed in.
Step 8. Now it's time to wire up the sub. My sub has dual 4ohm connectors. I wired these in parallel (positive to positive, negative to negative) to run it down to 2ohms. You'll then run a wire from the positive to the inside of the box, and same with the negative. See picture below
View media item 25623Screw the sub into the box!
Step 9. It's time to mount the amp. I mounted mine to the side of the box. You'll see the RCA wires from the line-connector, the power wire, ground wire, the amp turn on wire, the ground, and then the base adjust wire. You'll need to follow that same path of wires (power/amp turn on) that you ran from the front and run the base adjuster knob wire up to the front. I mounted mine on the inside of the drivers seat so I could reach it easily. See picture of amp and wires below
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Step 10. Turn on accessory power. In my LTZ with the push button start you just need to push the button once, not hold it down like you would to start it. You should get power to the amp and the sub should start working! Follow the manufacturer advice on tuning the amp. I'm keeping mine tuned fairly calm for a bit to allow for break-in time of the sub! You are done! Boom Boom!
