PLEASE READ THIS INFO ON TWO IMPORTANT SUBJECTS FIRST:
#1 - This is for a PIONEER SYSTEM. Not a NAKAMICHI, no matter how many times you ask!
Everything in this how-to was written for a Pioneer system
. All of the wiring locations and specifications were based on a Pioneer system
. If you have a Nakamichi
system, this DOES NOT
work as written. I can't help you with your Nakamichi system, though some people have posted in this thread how they got it to work.
#2 - IF YOU INSIST ON USING THE METRA HARNESS:
The second thing you need to know is I DID NOT USE THE METRA HARNESS.
That seems to be easy to understand right? I DIDN'T USE IT. But... people still try to and will ask me about it. Scanning through the posts made in this thread and in previous stereo-related threads, a few people maybe got lucky with the Metra harness and claimed decent results, but as far as I could tell most seem to have problems with it. It could be pin order, it could be some other reason - I wouldn't know and can't help you with it because I didn't use it. This how-to does NOT use the Metra harness and does not require it. I also do NOT recommend using it, as people seem to just have problems once they try using the Metra harness instead of following my how-to.
If you use the Metra
harness anyway even though it doesn't work really well, that's YOUR
If you use the Metra
harness anyway and not everything works right, I already told you it wouldn't, but you didn't listen.
If you use the Metra
harness anyway and you ask me how to fix it [/I]even if you already read this and knew I didn't use it
in this how-to, then honestly that's you're problem
- not mine. I didn't use the Metra harness for a reason.
Please get the two subjects above crystal clear before you decide to proceed. =) Thank you.
Revised disclaimers at the very top of the thread yet again
Added two disclaimers at the very top of the thread yet again
Revised wiring procedure for OEM subwoofer amp in section I; new wiring scheme allows head unit to power and have complete control of OEM sub amp and OEM antenna functions
Added install tip for more head unit clearance (for double-DIN head units) in section B; Direct link is here.
Added information on using home audio speaker wire; Added 4th item to parts list (15-feet of 18-ga wire); Updated section B. "MAIN CONNECTIONS" section; Extensively revised sections G, H, and I; installation no longer requires OEM main amp to function
Added "Compatibility Notes"
Clarified wiring in section C step 3
Added Metra harness text in post #1
Revised subwoofer/antenna fix; Updated harness diagrams for subwoofer/antenna fix; Added photo sample from RyanV
Added subwoofer/antenna fix; Updated harness diagrams for more clarity
On this and other boards I have gone through lots of info, all over the place, some contradicting each other, some REALLY confusing. This thread will try to clear it up and make it as easy as possible for my fellow SC owners. Some of the information below was compiled from other sources.
IS THIS THREAD FOR YOU?
For reference, this thread is for SC300/SC400 owners who can answer yes to ALL of the following:
1. I want to replace my factory head unit with an aftermarket one.
2. I still want to use my factory speakers.
3. I still want to use my factory subwoofer amp and subwoofer.
4. I want to use the amp of my aftermarket head unit to power the main speakers.
5. I DO NOT want to have to install any aftermarket amps yet.
6. I DO NOT install a separate amp for the subwoofer.
Any variation from above, and you're partly on your own. You'll need to be comfortable with cutting and splicing wires, and you'll have to remove the rear seats briefly. The goal here is to install an aftermarket head unit into an SC300/SC400, using the aftermarket head unit's built-in amplifier to power the main speakers (bypassing the OEM Lexus main amp) but using the OEM Lexus subwoofer amp to drive the OEM subwoofer. Because the OEM amplifiers are external (not part of the head unit) AND because there is no plug-and-play harness adaptor specifically made for our car, there's a little more work to be done, but not as hard as it may seem.
COMPATIBILITY NOTES (PLEASE READ!!)
I've recently learned that my how-to should be compatible with all 1992-1998
SC300/SC400 that has the Pioneer
double DIN factory head unit (radio/cassette/cd changer). The factory Pioneer setup has a 2.5-DIN radio/cassette up front, 12-disc CD changer in the right side of the trunk, the main amplifier (“main amp”) below the CD changer and the subwoofer amplifier (sub amp) on the rear deck between the sub and the right rear speaker. Image of the head unit is below:
If your factory head unit does not look like the one shown, I can't guarantee that you can use this thread, but it should be close. If your factory head unit is a 1999 model Pioneer with DIFFERENT plugs in the rear, I also cannot gaurantee that you can use this thread. Finally, If your factory head unit is a Nakamichi system, this probably won't work, or may work but not completely. Then you'll probably post here and ask me to solve your problem when you tried a Pioneer how-to on a Nakamichi system =P
WHAT YOU WILL NEED
1. Phillips screwdriver (Preferably with at least a 6" length to make the job easier)
2. Socket handle with a 10mm socket and 12mm socket
3. Wire cutters/strippers
4. Electrical tape
5. Masking tape to make wire labels
6. Sharpie marker to label each wire
7. OPTION soldering iron (for better connections)
8. OPTION heat shrink wrap (for better wire protection)
1. Crimp-on ring connector, with a hole large enough for a 10mm bolt
2. 60-foot spool of 18ga speaker wire from Radio Shack (part #278-0008, $11.00)
3. Single 18ga wire about 15 feet long, to be used for the OEM subwoofer amp
3. RCA-to-speaker wire from Radio Shack (part #42-2457, $9.00)
Using 18/4 in-wall speaker wire designed for home audio makes installation much easier (see section D for more info)
HOW LONG WILL IT TAKE?
The job will take about 3 hours if you know how to take your car apart, or 4-5 hours if this is your first time.
NOTE: Use my diagrams in this how-to article to reference wire locations!! The diagrams I made for this how-to are if you were looking at the factory harness plug face, with the wires coming out from behind the plug. Other diagrams (FSM, Intellexual, etc.) may be labeled different, so use the ones I’ve provided. The pins with the white boxes are the only wires you need to work with.
A. REMOVE THE OEM HEAD UNIT
1. Make sure you have a Pioneer head unit. As far as I know, Nakamichi head units say "Nakamichi" on the face of the head unit. Here's what mine looks like.
...and a look on the back shows the two harnesses we'll be using (they plug into the sockets labelled "A" and "D").
2. Follow my how-to here
to remove your OEM head unit. (If you're using the Metra double-DIN installation kit, the thread listed also shows you how to mod it to make it stronger)
3. Take a look inside the center console, right under the top of the dashboard, there should be two harness plugs (blue and white) against the firewall area. If you unplug these, you can pull the radio harness out more in order to give you more room when wiring your new head unit up. This is optional, but if you do unplug these two harnesses, don't forget to plug them back in before you reinstall the center console!
B. MAKE THE MAIN CONNECTIONS (Updated 07.30.12)
All of the main connections below should be universal to whatever aftermarket head unit you are installing, be it CD/Cassette/Digital Media, single-DIN or double-DIN. Make your wire connections clean, I soldered my connections and used shrink tubing to protect the connections (if you do the twist-and-tape method, that’s your choice.)
1. Connect your aftermarket head unit's main harness to the A-Harness as shown below.
15-pin plug with 14 wires, 7 per row, two rows, as shown below:
A-Harness Wire Color Guide
A1 pink with blue stripe and silver dots
A2 green (thick)
A4 blue with yellow stripe
A8 pink with green stripe
A9 white with green stripe
A10 no wire
A11 brown (thick)
A13 green (thin)
A15 brown (thin)
Here are the wires in the plug, and what to connect from your aftermarket harness:
A-Harness Connections (pin to aftermarket harness)
A1 - connect to ANTENNA wire (see NOTE 1 below)
A2 - connect to DIMMER wire (a.k.a.ILLUMINATION)
A3 - connect to ACC wire (12v+ switched)
A3 - OPTIONAL connect to 18ga single wire (see NOTE 2 below)
A4 – connect to POWER/BATTERY wire (12v+ constant a.k.a. memory)
A8 - connect to ANTENNA wire (see NOTE 1 below)
A11 - connect to GROUND wire (-) (see NOTE 3 below)
Yes – connect both A1 and A8 to the antenna wire from your head unit. This will raise the factory telescopic antenna whenever you use the radio. I also found that connecting both wires will ensure that the antenna will go DOWN whenever you are using any other source besides the tuner in your aftermarket head unit.
If your new head unit has an amp turn-on wire, extend it by connecting one end of the single 18ga wire in the parts list. If your head unit DOES NOT have an amp turn-on wire, connect one end of the 15-foot 18-ga. wire in the parts list to A3.
As for the ground at A11, I’ve read that this works for some people, whereas others grounded the head unit directly to the chassis. I elected to ground my head unit to one of the chassis bolts found on the transmission tunnel directly below where the radio sits, using the crimp-ring listed in the parts list above. If A11 works for you, great! If not, crimp a ring and ground your head unit to the chassis.
2. With these wires spliced, you can reconnect your car battery, turn your key to ACC, plug in your aftermarket head unit and do a "power on" check. There will be no sound since we haven't wired the speakers up yet (we’ll get to that soon!) but you'll be able to check if your head unit is working. All good? then turn off the key, unplug the battery again, and let’s continue.
If you have an aftermarket steering wheel installed, and you're installing a double-DIN head unit, here's a tip to get more installation space ---> go to this post
C. MAKE THE SUBWOOFER CONNECTION
To allow the OEM subwoofer amp to work with your aftermarket head unit, you’ll be using the RCA-to-speaker wire cable and the single 18ga amp turn-on wire.
1. Cut the RCA-to-speaker wire to about 8-inches long (when you buy it the speaker wire cable is 24-feet long!). Now locate the D-Harness.
2. Connect the RCA-to-speaker wire cable to the D-harness, as shown below.
10-pin plug with 10 wires, 4 on top and 6 on the bottom, as shown below:
D-Harness Wire Color Guide
D2 red with black stripe and silver dots
D3 purple with silver dots
D4 blue with white stripe and silver dots
D6 no wire
D7 no wire
D8 no wire
D9 no wire
D10 yellow wire with red stripe and silver dots
Here are the wires in the plug, and what to connect from your aftermarket harness:
D-Harness Connections (pin to aftermarket harness)
D1 – connect to RCA-to-speaker wire (-)
D5 – connect to RCA-to-speaker wire (+)
(thanks to twong 82
for figuring this out!)
3. When you're done, you should have something that looks like this:
EDIT: It was pointed out to me by triumph013
that I have the positive and negative switched in the photo; the side with the white stripe is supposed to be negative, not positive. I've updated the D-Harness Connections above to reflect this. However the only thing this affects is your subwoofer phase. If you followed the original wiring and your head unit has a subwoofer phase setting, just flip it. As for me, I can't really hear the difference so I left mine as is.
4. Plug the RCA end of the RCA-to-speaker wire cable into your aftermarket head unit's SUB OUT RCA plug. Your head unit is ready to send a signal to the OEM sub amp. But, we’re not quite done yet here.
D. EXTEND THE SPEAKER WIRES (Updated 07.30.12)
For the main sound, we'll be running speaker wires from the head unit location to the right-rear side of the car, in the trunk. This is to use the aftermarket amplifier (the one built-into the head unit) by bypassing the OEM factory amp, which coincidentally, is located in the right-rear side of the car, in the trunk. Some people have wired directly to the dash harness, but from research and by looking at the factory pin-out, the OEM sound system uses a common signal ground for the speakers. This is not the same as chassis ground! Some head units can be wired with a common signal ground, some can't. I didn't want to risk it, so I decided to run new speaker wire instead.
Yes - you can just run speaker wire from the head unit to each door, but that involves removing the door panels on each side, fishing cable through the door jam harness, etc.
During the course of rewiring my car awhile after writing this how-to I decided to remove the 4 pairs of speaker wire shown in the photos and I went with 18/4 (18-ga 4 wire) in-wall speaker wire designed for home audio. I bought a 100-foot spool for $33 on Amazon.com; obviously you won’t need this much, but like I mentioned I was rewiring my car. I’m sure you can find shorter lengths of this type of wire at larger hardware outlets or home audio specialists.
And a photo of the wiring in the trunk now:
The two groups of wires sticking out of the left side is the 18/4 wires already connected to the OEM main speaker wires. The larger bundle of wires on the right is the rest of the OEM wiring for the OEM main amplifier, which is now removed from my car (see below.) Back to the 18/4 wires: with 4 wires each it effectively separated the front speakers from the rear speakers and the color-coded wires made it much easier to keep track of what wire is which (red/black for left side, green/white for right side), not to mention much easier to run through the interior from the center console to the trunk.
The rest of step D (below) still applies; you’ll just have a cleaner installation if you use the 18-4 wiring like I did.
1. Grab that 60-foot spool of speaker wire and cut four equal 15-foot lengths. Connect each length of speaker wire to the speaker outs from the aftermarket harness. Use some masking tape and label each pair of speaker wires (FL, FR, RL, RR) because you’ll have four pairs of wire running from the dash to the trunk!
2. Your extended speaker wires AND amp turn-on wire (Don't forget the amp turn-on wire!) must go behind the passenger carpet, along the right side door sill, up the right side of the rear seat area, and into the trunk. First, remove the door sill trim piece; grab the trailing end, and pull up, it will just pop out from the sill mounting clips.
3. Now pull the rubber door seal to expose the sill clips even more.
4. Now carefully pull the sill clips from the door sill so that you can have access to the gap between the carpet and the door sill. This is where you'll be running those extended wires.
5. Now pull the front right edge of the passenger-side carpet, right below the edge of the dash.
6. With a little tugging, you'll be able to fold over the passenger-side carpet away from the footwell area, so you can run your extended wires.
7. I used some wire ties to keep the bundle of extended wires and amp turn-on wire nice and neat. Run this behind the footwell carpet.
8. Continue running the bundle of wires along the door sill, behind the carpet.
Run the bundle behind the dash, underneath the glove box, down to the right-side door sill, until you get to the rear seat area.
(continued next post)