Installing an Amp, Component Speakers and a Subwoofer
By: Bob_98SR5
Application: 98 4Runner V6 4x4
Written: 4/2/06


4 Channel Amp (mine is an old Crossfire CFA-404)
Q-Logic Kick Panel Component Speaker Enclosures
CDT Audio CL-51 Component Speakers
RE Audio 10" Subwoofer
Sealed subwoofer box
RCA cables
8 AWG power (Red) wire
8 AWG ground wire
Speaker wire
Fuse holder
Rubber Grommet
Ring connectors

Tools & Supplies
Philips head screwdriver
Tape measurer
Soldering Iron and Rosin-core solder
Wet Sponge
Cardboard box
Heat Shrink tubing
Matches or lighter
Alligator clips (2)
Self-tapping screws


I am providing this write up for illustrative purposes only. Perform at your own risk. Any mods (including this one) you perform on your vehicle is your responsibility. Commercial use of this write up will result in legal action as well as the undying scorn from members of the online Toyota 4Runner community. You've been warned.

This writeup is an extension of my head unit writeup. I decided that I wanted to upgrade my sound system since I started driving longer distances for my business as well as for vacation trips. Putting the knowledge together was not easy, especially if you have no idea how to do it, the terminology, etc.
Special thanks goes to Cebby, DavidA, Bumpin' Yota, and last but not least, NizAsnMonk (thanks for the hookup!).

This writeup is being written several months after I installed this system, so alot of this is from memory. If there are any glaring omissions or inaccuracies, please email me.

However, next to politics and religion, nothing stirs up more passion (and fights) than car audio. Personally, I don't give a donkey's ass if your stereo can kill mine, or that I should've bought this and that because "its the best." I am not interested in hearing about it. But again, if there is something that is incorrect, that is the feedback that I'd like to hear.

Step 1: Planning Your System Layout
Here are some questions you need to ask yourself:

- Where do you want to put your amp?
- Where do you want to put the crossovers?
- Where do you want to mount the subwoofer?

Those questions will help you lay out your system better, what equipment you will want to buy, and what length cables, RCAs, and speaker wires you will need to buy. Here is how I laid out my system:


My system layout was based on the premise to never compromise my rear cargo space. That meant the amplifier and the component speaker's crossovers had to be out of the way. I use my cargo space ALOT, so installing a large amp on the back of the seats (like many people do) was out of the question. That meant that I had to buy an amp that could fit neatly under the driver's seat. Also, I wanted the amp to be easily removed and not too big. Therefore, I purchased a box and a 10" subwoofer---a good compromise between size and sound.

From this point, take a tape measurer and begin to measure the distances from each component. Pad your figure a little just in case. Now I am going to explain everything from component to component.

Step 2: Clearing the Workspace

As always when doing electrical work, remove the negative battery cable first from your battery.

We'll begin by removing the front driver's seat. For the front seat, slide the seats forward and remove the end caps. Gentle pulling in a circular motion will most likely reveal which way to remove it. If you're not sure, you're going to have to poke your nose real close and look, but for the most part, they're easy to remove. After removing the rear end caps, slide the seats backwards and remove the fronts using the same methodology above. After removing the end caps, place them in the seatback pockets.
Take a 14mm socket and remove each of the 4 bolts. You may need to use a breaker bar. After removing the bolts, place them in the seatback pockets. Remove both front seats.

Remove the step panels on the front and rear passenger side by unscrewing the 4 and 3 philips head screws, respectively. Remove the step panel by pulling upwards. You can then pull off the kickpanel. And here's a great tip that you should do throughout this mod: use masking tape to tape the various screws and/or fasteners to the panels you remove. It's a great way of making sure you don't lose the fasteners. After removing the step panels, pull of the kick panel.

Repeat on the other side. Remove the front step panel and then the kick panel. There's no need to remove the passenger front seat nor the rear step panel.

Remove the four endcaps (C). Unbolt the seats w/ a 14mm socket. Unscrew philips head screws (S), tape to the panel itself. Then pull out kickpanel (K)   Trust me, you'll thank me for this tip when you start re-assembling everything!

Next, remove the bottom trim panel underneath the steering column. There are four 10mm bolts you need to remove. Once removed, unscrew the four Philips-head screws that hold the hood and gas tank hatch to the lower panel. Move the panel out of the way. Since you will be running your 8AWG power wire either through the existing firewall boot or drilling a new one (that's what I did), remove the A/C duct underneath the steering column. It is held together by a single Philips-head screw. After removing the screw, jiggle it out of the way.

Remove four 10mm bolts (4) and four philips-head screws (S)   Remove the single philips-head screw
and pull out the A/C duct

Removing the radio panel fascia is pretty simple and just requires the removal of a few knobs, dials, screws, etc. Begin by removing the knobs off your shifter and pulling off the shift boot cover. Next, remove the A/C knobs and dials. Put your fingers in the dial holes and pull out slightly. The A/C on/off switch should come out slightly. Pull it out. Finish by gently removing the A/C panel. It will snap out with a slight bit of pulling force.

Remove knobs (K), lift up (L). Optional: removing side screws (S) will make this job easier    Remove two knobs (K), two dials (D) and single AC switch (A). Remove AC face

There are three pesky philips head screws that securely fasten the radio panel fascia to your 4Runner. Remove those screws. Now you are ready to lift out the radio panel fascia itself. Begin by grabbing it from the bottom and pulling upwards and outwards. The radio panel fascia is clipped at the top. Once lifted out of place, remove the three harnesses located on the upper driver's side (hazard, clock and rear defroster). Continue by unfastening the bottom ashtray light (twist and pull out) and the cigarette lighter harness (unplug). Finish by moving this big hunk of plastic out of the way.

Remove screws (S). One is on the left and not shown in this picture    Unclip the three harnesses (H)

Step 3: Wiring Your Amplifier
Refer to the layout in Step 1. What I am about to describe is the red line (power) running from the battery to the amp as well as the single black line (ground) running from the amp to the amp.

My amplifier RMS is rated at 50 x 4. A stereo system running this load must use 8AWG wiring. Therefore, I hooked up a ring connector to one end of my red 8AWG cable and attached it to the positive battery post. Next, I mounted a 30amp AGU fuse holder on top of my fuse panel box with self-tapping screws. Cut your power cable to the proper length, strip about 1/2 to 3/4" of covering off, and screw it into the fuse holder. Remember, keep this length of power cable running from the positive battery terminal to the fuse holder under 12" in length. This part here is very crucial to your vehicle's safety. Should there be a short, the only wire that will burn and/or catch fire is this little cable. Here's a picture of the inline fuse and the 8awg cable running to and from it:

Now you'll need to run the rest of the power wire from the fuse holder to the amp itself. However, it is much easier to run the rest of the cable from the interior into the engine bay. Most people run it through the existing firewall, but I drilled a new hole in the firewall. Place an appropriate metal cutting drill bit on your drill and drill your hole. Run the power cable through the hole. Make sure there is enough to run to the amp as well as the fuse holder. Give it a good foot or two just in case.

After running the cable to the fuse holder, strip the protective covering off and then attach it to the fuse holder. At the other end, run your rubber grommet and slide it along the length of the cable until you can insert it into your new firewall hole. Run the power wire along the left side of your vehicle, down the door trim panel area, and then to the retangular metal "hump". Cut a small X-shaped hole and then run the power wire through it. Crimp on a ring connector to the end of that wire and then connect it to the 12V + connection on your amp.

Power cable with grommet Here is a shot of a rubber grommet test fitted for my 8awg power cable

From there, you will need to ground the amp. As with any ground that you do, make sure you take off some paint. I grounded mine near the seat. Crimp on a ring connector to the 8AWG black ground wire and attached it to the amp's ground connection point. Next, run that wire to your grounding point, scrape some paint off (a dremel sanding drum works best) and then crimp a ring connector onto it. Finish by using a self-tapping metal screw to securely ground your amp.

Step 4: Hooking Up the RCA Cable and Remote Lead Wire
The RCA cable, represented in the diagram by 4 plug magenta lines, allows the audio signals from your headunit to travel to your the amplifier. Each pair of plugs corresponds to each of the four channels: the left and right front and rear speakers. Of note, I have been told that you should not skimp on RCA cables, but there is no need to really buy high end stuff either. Thus, I bought middle of the road RCA cables.

On the RCA cable plugs, you should see that each set of plugs has two different colors. The other set of plugs have the identical colors. It really does not matter which color you use for the left and right channels---just be consistent. So for mine, i used the white end plugs for left speakers and the black ones for right speakers.

You will need to remove your head unit from the stereo chassis mounts. Use a philips head screw driver and remove the 4 bolts holding it onto the stereo chassis mounts. Set those bolts aside and then pull the head unit out.

Remove bolts (B)

Begin by plugging in the RCA plugs into the back of your head unit. Run the RCAs out the back and to the amp by running it under the center console. You can run it along the left side of the console and then run the RCAs down towards the amp. What I did was to cut another X hole where the RCAs connected to minimize the length of exposed RCAs for a cleaner look.

One key tip here: always keep your power cable and your RCAs physically separate from each other. This will negate any possible interference that the RCAs may absorb from the power cable. That is why I ran the power cable on the left side door panels while I ran the RCAs through the center:

Here's the RCAs hooked up to the amp Run the RCAs down the center

The remote turn on wire (shown as a green wire) turns the amplifier on and off, which allows both devices to work together. It's virtually instantaneous. For this wire, I used a green, 18 gauge wire.

From the headunit end, find the stereo wire harness. Look for the remote turn on wire and strip away some covering. Do the same to your green wire. Slip a small piece of heat shrink tubing onto one wire and then solder both wires together. Finish by heat shrinking the connected wires with a heat gun. Run that wire along the RCA wire's path and to your amp. Run it to the appropriate X hole and then crimp on a ring connector. Attach it to your amp's remote turn on lead terminal.

With this, you've completed hooking up the power, ground and remote turn on wire. Now we'll hook up the speakers wires from the amp to the crossovers.

Step 5: Component Speakers and Wiring Overview
One of the best things you can do for your sound system is to purchase component speakers. Component speakers are matched mid-range and tweeters with crossovers which allow for better sound output because of the ability to cleanly separate the highs from the mids. Your stock 4runner speakers and tweeters are lousy and channel all the mids and highs from your single stock speaker. More importantly, the "imaging" is not well-balanced with the stock speakers because of their location in the doors and in the window sail panels.

One recommendation I kept reading over and over is to purchase matched component speakers mounted in a kick panel enclosure. Fortunately for me, a few Yotatech members had already done this and were impressed. I also got a great deal on a used pair of Q-logic kick panel enclosures from a member as well as some CDT CL-61 components speakers with cross overs. Finally, I got a nice deal on a 10" RE Audio subwoofer and sealed box enclosure from member NizAsnMonk. PM him up for great deals on car audio!

Components come with a set of mids, tweeters and crossovers    Q-logic component speaker enclosures

As you read above, I decided to run a set of components up front and then a single subwoofer in the rear. That means that for the front component speakers, 1 channel will be taken by each side. So 2 out of 4 channels will be taken. The last 2 channels will be "bridged" into one channel for the subwoofer. Here is a good diagram of how the speaker cables are connected to their respective amp terminals:

One other thing: Many car audio enthusiasts say that in a vehicle like a 4Runner, it is best to unplug the rear speakers because of its negative effect on imaging. I'm not going to go into detail trying to explain it (because I can't, really), but I did follow the advice and unplugged the rear speakers. Its very easy: from the bottom of the panels, insert your fingers or a large screw driver until you can unfasten the door panel. Undo about 2 or 3 more. Then you can bend it back slightly and unhitch the speaker harness. It's right there. You can't miss it. Repeat for the other side.

Step 6: Hooking Up the Crossovers
In the master diagram above, refer to the blue wires from the amp to CO1 and CO2. As you see in picture above in Step 5, we are going to run two speaker cables *per channel* (speaker) to each of the crossovers. Here's a good picture to illustrate the connection points on the amp:

As you can see, there is a positive and a negative connection for each channel. The speaker wire colors are neutral. Just pick a color for negative and positive and stick with it (I picked blue for positive). Begin by stripping off the protective covering and crimping on ring connectors. Start with the left channel and unscrew the philips head screws until they are off. Fasten the speaker wires onto the connection points and screw down the screws. Do the same for the right channel as well. On the left channel wires, I wrapped the wires with black electrical tape to signify that it is the left channel. Do the same at the other end of the speaker wires.

Next, you will need to find a location for your crossovers. I tried mounting them inside the door panel as most people seem to do, but I did not like that location. I took some advice from NizAsnMonk and put them under my passenger seat. It is a very good spot for it, since they are so small anyways. I put some grip tape on the back of the cross overs, so they wouldn't slide around too. This works very well too.

Begin by cutting a small X shaped slit by the center hump. Cut a similar hole on the other side of the front passenger seat. For that hole, i cut it near the center of the seat area. Run the speaker wires under and over the center hump and to the front passenger hole. Strip the speaker wires, crimp on ring connectors and then fasten them to the appropriate positive and negative connections. Its a good idea to mark the left crossover with a piece of electrical tape, so you know which side is left and right.

View from rear passenger seat: hole (A) is used to feed the speaker wires to the crossovers. Hole (L) is the speaker wires running to the front speakers. Hole (R) is the hole used for the right speakers

Now you are ready to connect the speakers.

Step 7: Connecting the Front Component Speakers

You'll be mounting your component speaker's main mid-range speakers and the tweeters onto the Q-Logic kick panels. Measure the outer diameter of your speakers and then cut the appropriate sized hole on the kick panels. Repeat for the other side. After doing a test fit, remove the speakers.

A little optional step: After reading a few reviews, many people said that reinforcing the back of these kick panels with fiberglass was a good idea to stiffen them. Also, many people stuffed the back with polyfill. I did both, but again, these are optional steps. When dried and satisfied, screw down the mid range speakers.

That yellowish color is the fiberglass    The fuzzy stuff is polyfill

For the left components, take some speaker cable, crimp on two ring connectors and connect them to the crossovers. Cut a small x-shaped hole near the crossovers. Feed the speaker cable through, run it up the center console area, make a left turn across the clutch, brake and gas pedal area, and then back towards the left component speakers. Finish by crimping on blade connectors for the mid-range speakers and soldering the tweeter wires together. Run the speaker cables from both the midrange and tweeters to the left crossover.

For the right components, it's a much shorter trip. Crimp on ring connectors and connect them to the crossovers. Cut a small hole right by the rectangular hump near the front passenger seat. Run the speaker cable from the components towards the step panel and then run the length of that speaker wire to the right components. Finish by crimping on blade connectors for the mid-range speakers and soldering the tweeter wires together.

You are looking at a view from the front passenger seat. As you can see, I ran the speaker cables under the seat, along the door step panels and then to the component speakers    Here's the speaker cable running towards the right component speakers

Finish by fitting both Q-logic kick panels into the old kick panel location by simply pushing them in. There are no "snaps", so just firmly push them in. Here is what it should look like:

Step 8: Connecting the Subwoofer
This is an easy one which does not require hooking up speaker cable to the crossovers. Crimp on ring connectors again and screw these down to the *outermost* positive and negative connection points. This will "bridge" the two remaining channels into one. Run this wire under the carpet away from the power cable, towards the step panel, and then along the length of the rear passenger step panel. Cut an exit hole for this subwoofer speaker wire and then run it towards the rear cargo hatch. I ran enough to the back so I could place the subwoofer anywhere in the rear. Strip the speaker wire ends, twist the wires tightly, and then run some solder through these speaker wires to make a good connection. Connect them to the positive and negative connection points on the subwoofer.

All amp connections done! (G) is the ground, (R) is the remote wire, (P) is the power wire, (L) is the left channel speakers, (R) is the right channel speakers, and finally, (S) is the subwoofer speaker wires.    Here's the subwoofer. The 10" sub is a manageable size: for comparison's sake, I fit my 32" spare back here with no problem.

I'm sure by now, you're just itching to test it. Reconnect the negative battery cable and give it a go. If it works, you're golden. Test out the left and right channels independently of each other. Test out the subwoofer and make sure it is pushing some bass. If you are happy, reattach all panels, seats, step panels, as well as the head unit and center radio fascia. Here's a shot of my completely connected amp without the seats as well as a shot of the exposed amp controls with maglite. I can't exile my trusty Maglite, now can we?

For my first install, I'm very happy with the fit and clean install    As you can see, the Maglite can still fit and the amp controls are still accessible

Here's one more picture of the install from the driver's side passenger seat:

With a little room to spare, the rear Husky liners butt up against the amp, but mercifully, they do not need to be cut.     

Step 9: Additional, Optional Tips
I recommend securing the subwoofer with a ratcheting strap. Use the end points that are anchored into the floorboard.

Also, if you have Husky Liners, you will need to make some creative cuts. Carefully eyeball the cut locations and make your first cut. Use a pair of medical scissors to make a nice, flush cut around the Q-logic speaker enclosures. Please note that the cut locations of the right speakers are completely different than the left. See the pictures below that illustrate my "cut first, measure twice" mentality :)
Nice, flush cuts on the driver's side Husky's    Eh...bearable, not-so-flush cuts on the passenger side Husky's

Questions or feedback? Email me and I'll try to get back to you. If this article helped you save time, money or just made things more convenient for you, please consider donating to keep this site alive.