This is not quite a writeup, but more so some notes I took when installing my new stereo because while I was researching threads here, I didn't really find all the info i needed.
1995 LS400, Came with the Pioneer head unit and 6 Disc changer, NOT NAKAMICHI!
My objective was to install an aftermarket head unit, subwoofers and amplifier, but still retain the factory speakers in the doors, and disconnecting the factory 8" sub.
Aftermarket pioneer doubledin head unit.
2 12" Subwoofers
Hifonics Mono sub amp.
OEM Speakers with factory amplifier.
I used this wiring diagram to figure out the wiring i needed to do http://www.mediafire.com/file/n2ygzzmzf53/lf1rap96.pdf
. You WILL need basic knowledge of wiring diagrams to do this, but I'll TRY to make it as simple as I can.
Basically all you will need to do is wire in 4 RCA jacks to your factory wiring to plug into the back of your new head unit, and wire up 1 more wire to turn on the factory amplifier for your door speakers.
Looking at the pictures of the plugs in the wiring diagram, you will only be needing to use plugs "R 2 B" and R 3 C GRAY"
You will be cutting the wires that go to the factory plug and soldering on RCA Jacks. It is easier to buy a cheap RCA cable with 4 Male ends, and then just cutting the plugs off with about 5-6 inches of wire still attached.
Take a White RCA Jack and solder the Green wire from pin 14 of plug B to the negative lead of the RCA Jack.
Solder the Red wire from pin 5 of plug B to the positive of the RCA jack. This is for the Rear Left speaker.
Take a Red RCA Jack and solder the White wire from pin 7 of plug B to the negative lead of the RCA Jack.
Solder the Black wire from pin 2 of plug B to the positive of the RCA jack. This is for the Front Left speaker.
Take a White RCA Jack and solder the Green wire from pin 13 of plug B to the negative lead of the RCA Jack.
Solder the Tellow wire from pin 4 of plug B to the positive of the RCA jack. This is for the Rear Right speaker.
Take a Red RCA Jack and solder the Red wire from pin 6 of plug B to the negative lead of the RCA Jack.
Solder the White wire from pin 1 of plug B to the positive of the RCA jack. This is for the Front Right speaker.
Now these are ready to plug into your new head unit. DO NOT just skip wiring in RCA's and just wiring them into the Speaker wires coming out of your new head unit! Those wires are Amplified wires that are meant to go to un-amplified speakers. Just tape those up because they are unused.
Take the Pink wire with blue line (i think it was a blue line, just look at the pin location on the plug) from pin 11 plug B and solder that wire to the "REMOTE" or "SYSTEM REMOTE CONTROL" lead on your new head unit. This will turn on the factory amplifier.
The Gray wire, pin 6 on plug C can be used for the ACC wire on your new headunit.
Do not use the factory head unit 12V power wire to power your new headunit, chances are the wire is too small, just run a thicker wire to a 12V constant source.
Ground the head unit to the steel brace/tube behind the dash, you'll see it right in front of your face when your factory head unit is out. I just used a self-tapping screw. Just make sure it makes good contact to the metal tube.
As for the rest of the plugs that you don't use, I just taped them up and tucked them away, they are un-needed.
A few quick notes:
Your factory changer will not work anymore (it won't work with your new head unit anyways.)
The factory amplified speakers get LOUD, and I mean LOUD and still sound clear. I am running 2 12" alpine Type R's in a ported 1-1.5 cu/ft enclosure and they still sound very loud and clear enough to hear over the Bass.
The factory subwoofer can just be unplugged and removed. No need to remove the factory amp and wiring for it, just tuck the wire away.
Some people will tell you that you need some sort of Hi/Lo converter for this install, but this is NOT true. The only time you will need this is if you use the FACTORY HEAD UNIT with AFTERMARKET SUBWOOFERS!
Any other questions feel free to ask!