Installing an Aftermarket Head Unit
By: Bob_98SR5
Application: 98 4Runner
Written: 7/28/04


Aftermarket Head Unit (this one is a Clarion DXZ545MP)
Metra Harness #70-1761 (fits all Toyotas from 1987 and up)
Metra compartment box (if you have a free DIN slot you need to fill up)

Tools & Supplies
Philips head screwdriver
Soldering Iron and Rosin-core solder
Wet Sponge
Cardboard box
Heat Shrink tubing
Heat gun, matches or lighter
P-touch label maker (optional)
18-gauge power (Red) wire
Alligator clips (2)

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 based on the assumption that you have a stock Toyota stereo installed in your vehicle and you are installing a Clarion DXZ545MP head unit only (no amps) to four stock speakers. Also throughout this writeup, I'll be interchangeably referring to my new Clarion head unit, "new head unit", and my old, stock Toyota head unit. Please keep that in mind when reading this writeup.

So my learning experience began when I decided that I wanted to get a new head unit to replace my stock one primarily because I wanted a head unit that had MP3 playing capability. Thus, I purchased a Clarion DXZ545MP, a quality, moderately priced and full-featured head unit that fit my budget and needs. Now selecting a head unit was the easy part. Wiring it up without the plug-and-play Crutchfield harness was another!

I'm a total novice to stereo systems and how they work. Special thanks to DavidA who answered several of my newbie emails and went above and beyond with recommendations on equipment and where to buy it. Thanks, David! Also, Cebby provided me with another great piece of advice for any car stereo/electrical work you do: do NOT use a Test Light. Use a multimeter if you are trying to probe voltage for any wires. Using a test light may cause weird things to "trigger", up to and including deployment of your air bag. Here is an additional warning (verbatim) from one of my favorite websites on anything car audio electric, "Basic Car Audio Electronics":

"If you're not probing anything other than the wires going into the radio or the amplifier, the test light is safe. If you're testing the voltage in any other connector under the dash, you absolutely MUST use a digital multimeter."

Ok with that, read on and take note of the little details that will make this job a lot easier.

Also next to politics and religion, nothing stirs up more passion (and needless internet drama) than car audio. Personally, I don't give a rat'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. This article is older than dirt now, but the wiring and approach is still the same with new equipment too. But again, if there is something that is incorrect, that is the feedback that I'd like to hear.

Step 1: RTFM (Read the Bleepin' Manual)
First off, the process itself is very simple. However, getting the right results the very first time takes patience and planning. This is especially important if this is your first time wiring a harness together because you have many wires that need to be soldered. So take your time and get it right the first time. And as always, read your stereo's installation manual a few times to get yourself familiar with your stereo's wiring schematics. Once you familiarize yourself with it, review your Mertra harness wiring color chart too.




Yes, this picture is small. Deal with it!


Here are the Metra Harnesses

For the map above and from left to right, your stereo will be connected by a series of harnesses. My Clarion stereo came with a harness (SH) which has the plug harness at one end and the loose wires at the other. To mate these wires, I purchased a Metra Harness #70-1761 which comes with two harnesses. You need to solder the Metra harness wires to the Clarion harness wires. This will allow you to plug your Metra harness into your 4Runner's stock harness.

Point S is where we will focus most of our efforts on in this writeup. Point C is simply plugging the two harnesses into each other.

Step 2: Labeling and Soldering Your Harness Wires

Grab the head unit and Metra wiring chart/schematics, your soldering supplies and your P-touch label machine. Using the charts as a guide, label each and every wire carefully. The time spent here will make your soldering job exponentially easier and accurate. Follow the reference wiring diagram from your manual as well as the Metra harness wiring guide on the back of the packaging.

Most of the wires are easily matched up to each other. However, there are some wires that I labeled but didn't need to be soldered to any other wires. Also, there were some wires that had C-type connectors crimped on. I simply cut them off and stripped them to be soldered to other wires. Here are the odd-ball ones for your reference. Please note that there is only one Clarion harness while there are two Metra harnesses:

Clarion Harness

Metra Harness (Large)

Metra Harness (Small)

  • Blue/White: Amp Turn on (Leave free if no amp)
  • Brown: Phone Mute (leave free if no phone mute device)
  • Black- cut off connector and soldered to Metra black wire
  • Yellow 15 Amp Memory- cut off connector and soldered to Metra yellow wire
  • Yellow 3 Amp - Bus power wire that is your power wire to your car's battery. Needs to be soldered to a longer wire and crimped to an O-ring and attached to your battery's positive terminal.
  • None
  • Orange/Black: Negative Dimmer (left free)

After labeling all the wires, do a test matching of the Clarion and Metra wires. Of note, the Metra purple wires are almost black in color. It is especially difficult is to pick out the purple/black wires. Thus, look under a very bright light and determine which one is positive and negative.

Your next task is to solder the wires together. While there are many methods for soldering wires, I prefer heating up a small amount of solder on the soldering tip first, applying the newly tinned tip to the wire, and then pressing the solder wire onto the wire where it should easily melt and flow through the wire fibers.

Here, pay attention to Steps 1 and 2. In Step 2, you really only need to do Figure 10, 11, and 12. Step 3 is not relevant. One step that is not included is putting on a piece of heat shrink tubing on the wire before soldering. Once the solder has set, move the heat shrink tubing above the soldered joint and then shrink with heat from a match or lighter. See my labeling and soldering work below:




Here are the two fused Clarion power wires and how I labeled them


Some wires labeled, soldered and heat shrunk

Step 3: Removing Radio Panel Fascia
As always when doing electrical work, remove the negative battery cable first.

Removing the radio panel fascia is pretty simple and just requires the removal of a few knobs, dials, screws, etc. Here is Crutchfield's diagram of how to remove it. But mine is better, so read on ;) 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.

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

Step 4: Removing the Stereo and Amplifier
There are total of four screw bolts holding the stereo's "cage" onto your 4Runner. Remove those screw bolts and gently pull the entire unit out. There is a single harness coming from the amp that is attached to the back of the stereo as well as the power antenna plug and the power plug to the stereo. Remove everything and then pull out your caged stereo. Next, unscrew the two screws that are securing the amp to your 4Runner. Pull that out as well and unplug the two harnesses behind it.






Remove screw bolts (B). Unplug everything behind the stereo


Unscrew screws (S) and lift amp out


Unclip the two harnesses (H). These harnesses are harnesses T1 and T2 in the very first "map" picture in Step 1

Step 5: Out With The Old, In With The New
There are a total of 6 screws holding your stereo (and compartment box, if single DIN stereo) into the cage. In my case, I have a single DIN stereo with an old compartment box that didn't work. Begin by removing all screws and screwing in the new parts. I chose to install a Metra compartment box I had lying around.




Loosen bottom screw (S) and remove/replace the compartment box.


Snap off trim ring (T). This was not needed for my 98 4Runner

Also, you won't need the metal cage that most aftermarket stereos come with nor the plastic trim ring for perfect fitment in your 4Runner. Remove both before screwing in your new stereo.




Lift up tab (T) on both sides of the new stereo to remove the metal cage


Installed as shown

Plug in your new stereo's harness kit into the back of your stereo. Then connect your Metra harnesses into both the stereo's harness kit and to your 4Runner's harnesses. Plug in your antenna and power plugs into the back of your stereo. Now you are ready to power it up for a test run.

Step 6: Test Run and Finalize Installation

There are two ways you can wire your stereo. You can directly connect it to your battery or to a switched 12 volt wire. I will describe the battery method below.

Unwind a length of positive 18 gauge wire that is long enough to run the distance from the back of your stereo, underneath your driver's side floorboard (near the pedals), through the firewall, and to your 4Runner's battery. Next, strip both ends. Temporarily twist one end to your 3 Amp yellow power wire from the Clarion harness. Secure it with an alligator clip. Next on the other end of the 18 gauge power wire, screw it down onto the alligator clip and then clip it to any ring terminal that is attached to your battery's positive terminal. Screw down your negative battery cable onto its terminal and then turn your vehicle on (just the battery) without starting the engine.
Turn on your stereo to see if it works. For my Clarion head unit, there was an "initialization" period which only lasted a few seconds. It worked perfectly the first time and hopefully if you've followed this process, so should yours. :)
After testing, turn off your vehicle and again remove the negative terminal. Next, solder the 3 Amp power wire to your 18 gauge power wire. Re-attach your stereo cage back into your 4Runner, run the positive wire underneath your driver's side floor board, through a firewall grommet, and then solder/crimp on a ring connector. Fasten that to any point on your ring terminal post (positive side, of course) and then reattach your negative battery terminal.




I ran the stereo wire underneath the carpet and through my firewall hole


I ran the power wire through one of my own grommeted firewall holes (G)

Reattach all the radio panel fascia pieces in reverse order. Here's a pic of it installed in the 4Runner with the Metra empty DIN storage compartment beneath. Of note, I found this Metra pocket utterly useless for keeping things inside without it spilling out on even moderately sloped hills. Find one that slides out like a dresser drawer.


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.