How to install a headunit in a Lexus SC 300 400
#1
How to install a headunit in a Lexus SC 300 400
Ok since there is no real thread on how to do this properly I decided to make my own.
My stock system consisted of the following,
Nakamichi Head unit
12 Disc CD Changer
Toyota Pioneer Amplifier (don't know why if my headunit was a Nak)
Factory Subwoofer
I used this guide first (but read further because this don't tell you everything!!)
Constant 12V (+) - Blue/Yellow
Ignition Switched 12V (+) - Grey
Antenna - Pink/Blue AND Pink/Green
ILL 12V (+) - Green
Ground ( - ) - Simply crimp on a ring connector to the stereo harness and ground under the bolt to the body directly under the stereo - no need to tap that.
Now for the speakers.
Since our cars all have a factory amplifier you have to either run a line level converter or wire direct to the speakers. Or turn the RCA's into speaker wire and run them all to the amp............Besides the direct approach,This is all ghetto rigging.
This is what I did.
The system in the car is like a computer essentially, it's 12 years old and obsolete. If this were home audio equipment this would not be the case. But it's car audio so let's be honest.....it was not the best in 1995 and it's not the best now.
I am a Mcintosh audio guy trust me I know what I am talking about.
1. Take out the factory amp and the changer, and install your head unit harness awhile.
2. Make 4 lengths of wire 13-14ft long.
3. Mark wires such as FL FR RL RR (on both ends trust me it's easier)
Here is the wiring guide for the rear compartment area where the amplifier and changer was.
Driver front Pink and Purple wires (Pink Positive)
Passenger front Blue and Aqua Green Wires (Aqua Green Positive)
Driver rear Yellow and Black wires (Black Positive)
Passenger rear Red and White wires (Red positive)
Provided no one ever messed with the wires this will be the correct polarity, you may have to verify. But, at least you know what wires go where.
These are all on the same plug.
4. What you are going to do is wire these up first
5. Once wired you will see a little latex wire plug where the factory wires go through the bottom. It is up near the right trunk hinge. Poke this with a screw driver or do something fancy if you want.
6. This is a great place to put your wires through.
7. Run them through the hole and down next to the seat. ( you may need an extra set of hands)
8. Pull up the passenger side carpet trim and run the wires under the carpet along the seat rail. You will see the factory wires running down there.
9. Pull up the carpet in the passenger footwell and tuck the wires nicely.
10. Continue to wire the speakers to the headunit harness.
This is why you label both sides (you did label each side right?)
Now try everything out you should have your system up and running.
This is the best way to do it other then running wires right to your doors and rear speakers.
In most cases if you are installing a MP3 player you are getting 12 discs + full of music anyway. And if you also get a 6 disc changer you are well ahead of the game.
So in ending this is basically like having a normal car and going the full install route. That is installing amplifiers and headunit.
You are actually bypassing the amplifier and using the internal one in your headunit. You will also have the option of later adding amplifiers easily. So maybe you can run your RCA wires awhile.
The wiring diagram may or may not work on your car. The wires that are mentioned above are all on the same harness. There will be two remaining wires and they are Brown and Blue/yellow.
My stock system consisted of the following,
Nakamichi Head unit
12 Disc CD Changer
Toyota Pioneer Amplifier (don't know why if my headunit was a Nak)
Factory Subwoofer
I used this guide first (but read further because this don't tell you everything!!)
Constant 12V (+) - Blue/Yellow
Ignition Switched 12V (+) - Grey
Antenna - Pink/Blue AND Pink/Green
ILL 12V (+) - Green
Ground ( - ) - Simply crimp on a ring connector to the stereo harness and ground under the bolt to the body directly under the stereo - no need to tap that.
Now for the speakers.
Since our cars all have a factory amplifier you have to either run a line level converter or wire direct to the speakers. Or turn the RCA's into speaker wire and run them all to the amp............Besides the direct approach,This is all ghetto rigging.
This is what I did.
The system in the car is like a computer essentially, it's 12 years old and obsolete. If this were home audio equipment this would not be the case. But it's car audio so let's be honest.....it was not the best in 1995 and it's not the best now.
I am a Mcintosh audio guy trust me I know what I am talking about.
1. Take out the factory amp and the changer, and install your head unit harness awhile.
2. Make 4 lengths of wire 13-14ft long.
3. Mark wires such as FL FR RL RR (on both ends trust me it's easier)
Here is the wiring guide for the rear compartment area where the amplifier and changer was.
Driver front Pink and Purple wires (Pink Positive)
Passenger front Blue and Aqua Green Wires (Aqua Green Positive)
Driver rear Yellow and Black wires (Black Positive)
Passenger rear Red and White wires (Red positive)
Provided no one ever messed with the wires this will be the correct polarity, you may have to verify. But, at least you know what wires go where.
These are all on the same plug.
4. What you are going to do is wire these up first
5. Once wired you will see a little latex wire plug where the factory wires go through the bottom. It is up near the right trunk hinge. Poke this with a screw driver or do something fancy if you want.
6. This is a great place to put your wires through.
7. Run them through the hole and down next to the seat. ( you may need an extra set of hands)
8. Pull up the passenger side carpet trim and run the wires under the carpet along the seat rail. You will see the factory wires running down there.
9. Pull up the carpet in the passenger footwell and tuck the wires nicely.
10. Continue to wire the speakers to the headunit harness.
This is why you label both sides (you did label each side right?)
Now try everything out you should have your system up and running.
This is the best way to do it other then running wires right to your doors and rear speakers.
In most cases if you are installing a MP3 player you are getting 12 discs + full of music anyway. And if you also get a 6 disc changer you are well ahead of the game.
So in ending this is basically like having a normal car and going the full install route. That is installing amplifiers and headunit.
You are actually bypassing the amplifier and using the internal one in your headunit. You will also have the option of later adding amplifiers easily. So maybe you can run your RCA wires awhile.
The wiring diagram may or may not work on your car. The wires that are mentioned above are all on the same harness. There will be two remaining wires and they are Brown and Blue/yellow.
Last edited by 1997sc300; 05-29-07 at 03:01 PM.
#3
Hello,
My trim panel that goes around the head unit and the climate control is in mint condition. I was going to order another one (used) and fiberglass and bondo the double din opening to a single. Since my car has black interior a flat black paint will match nicely. I was planning on getting a double unit down the road so I will just sell the one I bought and modified later.
For now it is mounted using the factory brackets and it has the gap under it.
#5
#7
Driver front Pink and Purple wires (Pink Positive)
Passenger front Blue and Aqua Green Wires (Blue Positive)
Driver rear Yellow and Black wires (Yellow Positive)
Passenger rear Red and White wires (Red positive)
I believe your wiring color code is wrong.
It should be:
Driver front Pink and Purple wires (Pink Positive)
Passenger front Blue and Aqua Green Wires (Light Green Positive)
Driver rear Yellow and Black wires (Black Positive)
Passenger rear Red and White wires (Red positive)
The way you have it now, both your front and rear speakers would be out of phase, meaning a lack of bass.
Unless you rewired all of your speakers at the speaker, you should change your wiring.
Passenger front Blue and Aqua Green Wires (Blue Positive)
Driver rear Yellow and Black wires (Yellow Positive)
Passenger rear Red and White wires (Red positive)
I believe your wiring color code is wrong.
It should be:
Driver front Pink and Purple wires (Pink Positive)
Passenger front Blue and Aqua Green Wires (Light Green Positive)
Driver rear Yellow and Black wires (Black Positive)
Passenger rear Red and White wires (Red positive)
The way you have it now, both your front and rear speakers would be out of phase, meaning a lack of bass.
Unless you rewired all of your speakers at the speaker, you should change your wiring.
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#8
Driver front Pink and Purple wires (Pink Positive)
Passenger front Blue and Aqua Green Wires (Blue Positive)
Driver rear Yellow and Black wires (Yellow Positive)
Passenger rear Red and White wires (Red positive)
I believe your wiring color code is wrong.
It should be:
Driver front Pink and Purple wires (Pink Positive)
Passenger front Blue and Aqua Green Wires (Light Green Positive)
Driver rear Yellow and Black wires (Black Positive)
Passenger rear Red and White wires (Red positive)
The way you have it now, both your front and rear speakers would be out of phase, meaning a lack of bass.
Unless you rewired all of your speakers at the speaker, you should change your wiring.
Passenger front Blue and Aqua Green Wires (Blue Positive)
Driver rear Yellow and Black wires (Yellow Positive)
Passenger rear Red and White wires (Red positive)
I believe your wiring color code is wrong.
It should be:
Driver front Pink and Purple wires (Pink Positive)
Passenger front Blue and Aqua Green Wires (Light Green Positive)
Driver rear Yellow and Black wires (Black Positive)
Passenger rear Red and White wires (Red positive)
The way you have it now, both your front and rear speakers would be out of phase, meaning a lack of bass.
Unless you rewired all of your speakers at the speaker, you should change your wiring.
The previous owner upgraded the speakers to generic Pioneers and the wires must have been switched at some time in their life.
I updated the post to match your info thanks again.
#10
Damn, this thread is old... I'm about to install a double din aftermarket HU. I have a 92 SC300 so I take it that it has a Pioneer and not a Naka unit. I been searching and reading around that the 92-95 models(wire diagrams) are different than the 96-00. Is this true? Would this info that 1997sc300 and RICH001 help me? Or, are the wire color codes different?
#11
#12
Does anyone know how the wire bundle from the car should attach to the power antenna relay? Here is a pic of what I'm working with - needless to say, the antenna isn't doing anything... I'd even be fine with putting in a plain ol' low profile antenna that doesn't go up and down. Just not sure about this mess of wiring!
Also, I noticed a couple of wires that looked like they had a coax connector on the end. One is black and attached to the bundle of wires on the inside back of the trunk, and the other is gray and coming through to the antenna side of the car from the front. Neither wires are plugged into anything. What are these for?
Also, I noticed a couple of wires that looked like they had a coax connector on the end. One is black and attached to the bundle of wires on the inside back of the trunk, and the other is gray and coming through to the antenna side of the car from the front. Neither wires are plugged into anything. What are these for?
#13
Also, I noticed a couple of wires that looked like they had a coax connector on the end. One is black and attached to the bundle of wires on the inside back of the trunk, and the other is gray and coming through to the antenna side of the car from the front. Neither wires are plugged into anything. What are these for?
Grey one could be for your radio antenna. My antenna does not go up and down (but motor runs), i just set antenna to be about 1' up (wont go much shorter) and i get ok reception.
1997sc300 - Props for great thread the wire polarity's helped me
rich001 - thanks for checking the polarities
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