I'm sorry to say that there's a lot more to it than just "to change out" the stock head unit. This because the head unit only delivers low level signals, which leads to a custom amplifier (under the passenger seat).
Anyhow, it can be done. There are custom made fitting kits (from Metra) for ISO and double ISO head units available. I've done a total overhaul (new speakers, amplifiers and head unit) of the audio system on my 95' (which is the same generation as your 96') and it wasn't that hard, just a lot of work. I replaced/upgraded all the door speakers from 4" to 6.5", which gave a sound which I'm very pleased with.
Anyhow, check this thread for wireing etc: https://www.clublexus.com/forums/ls4...-diagrams.html and this site for how to access the head unit: http://www.lexls.com/tutorials/audio/ (these tips are for the first gen. LS400, but much of the info is still valid).

//Björn

 

I need to keep the amp running to power my stock sub, i installed an Alpine head unit with harness but nobody seems to sell a harness that powers the factory amp! just the speakers i called Tech support and they told me to find the amp power (blue/white) and connect to the blue/white coming from the harness i did this, the amp has power but no sound is going to the sub, can anyone help?

 

i could be wrong since i don't know the 2ls well but if it's like the 1ls the above is only true for the nakamichi system. a quick search on ebay leads me to believe there was a non-nakamichi system which would only need a standard wiring kit.

another option would be thye beat sonic dash kit which has an integration harness:
http://shop.beatsonicusa.com/product...9&categoryId=2

a little update on my (now removed) system:



old school eclipse ecd-414 hu (soon to be replaced with an eclipse avn20d)



dls iridium 8.2i components (8" mids in the doors, now replaced with hi-vi cf140 coaxials i was using as rear fill)



dls ra20 amplifier and whatnot (was going to run an ra10 and oa8 but pulled everything instead, going back to stockish)

 

I wanted to first say how much I appreciate the other members of this awesome forum. Their wealth of knowledge has truly been a blessing to me and my ’99 LS400. This is my first post to the site, and I hope it helps someone in their quest for audio bliss.

I have always installed aftermarket audio gear in just about every car I have owned. Since my purchase of the said LS in March 2008, I have contemplated and wavered about the direction I wanted to take her. I finally sacked up, and jumped in with both feet installing a modest yet practical everyday audio upgrade. Being a married father of three, my justification for spending a lot of hard earned scratch simply was not there. I have salvaged some quality componentry from some of my former rides, and I chose to use these in the present application.

Components used:
Sony CDX-GT410U (head unit)
Phoenix Gold MPS- 2220 (amplifier) an oldie but goody
1 Farad Boss Audio Capacitor
(1) 10” Audiobahn Alum10Q subwoofer

The goal of the system was to create some system flexibility (i.e. aux. input, in-dash cd, mp3 compatibility), while providing some low end punch that adds depth and warmth to a variety of musical selections. My other main consideration was not to physically alter an already sweet ride. I photo documented the entire install that took approx. 30 hours. I will post the step by step procedures as I have time. Thanks again for a rockin’ forum, and I look forward to sharing.

Desert 400

 

You can always tell a DIYMA member. BIG *** midbass, yes!

Looks nice dude!

 

looked nice. that entire system is removed.

my new setup will consist of:



eclipse avn20d (nav, no dvd, no preouts)



hi-vi cf140 4" coxials (6db hpf @800hz)



tang band 4" underhung "midbass" (fullrange)

i did go all out on a beat sonic dash kit though (). preparing to park the ls or get rid of it.

 

could anyone tell me where the best place (or a couple options) to run a power cable for an amp through the firewall would be?

 

i found through the grommet on the wheel well along the wiring harness into the driver kick panel to be the best option. that's a 92, might want to mention your year.

 

good point, i thought i did. on a 99 ls400

 

1999 LS400
Amplifier and Capacitor Install in Trunk: pt.1
I first decided to mount the amplifier and capacitor in the trunk along with the sub. This required power to the rear of the vehicle. I searched the forum for a clean way to get through the firewall, but was unsuccessful. I finally took out the glove box, and located a wire loom running through a silver dollar sized rubber grommet on the right side of the firewall. (See attached photo #1) This wire loom exited into the engine compartment near the passenger side hood hinge. I pulled the rubber grommet out exposing the hole in the firewall. Next I popped the other plastic grommet loose in the engine compartment. Using a wire coat hanger, I threaded it through the engine compartment side down through the hole in the passenger foot well. (My wife helped by wiggling the hanger when I felt it was close enough to grab with my fingers). I then attached the power wire to the hanger with duct tape, and pulled it through the firewall.

I chose to route the power, rca, and remote turn-on, wires to the trunk. I’ll post how this was accomplished later. Gotta go change a diaper. Audio bliss is not far away!

 

perfect, thanks!

 

capacitor = unnecessary load on the electrical system.

Otherwise, great pic of the entry point.

 

I used to have big bass in a former system that drew a lot of amperage from the alternator. The capacitor is left over from that system, and I decided to mount it now since I haven't decided if I will install a larger amp to power the subs. I agree in a small wattage system, a capacitor is not necessary, but I have also driven down the road with dimming headlights at every bass tone. Not a very safe situation.

 

Not to derail the thread, but I want to point something out here...

A cap doesn't help with headlight dimming unless it is at the headlights. Even then, you need an incredible amount of capacitance to handle this.

In my vehicle currently, I have a true RMS-capable Phoenix Gold 1200W sub amp, and a similarly powerful 78x4 main amp. There is No dimming at all. I have learned the amps themselves need to be of high enough quality to contain the proper capacitance from within. Since most amps sound exactly the same to the human ear all other variables set equal, one thing you can count on is that an amp with higher onboard capacitance in the power supply and the output stage of its circuits, the better suited it is and the better choice it is to buy.

I'm not saying that PG amps are the holy grail, far from it. But for my situation, and my musical tastes (LOUD, and clear without compromise), they suffice.

The other thing that greatly helps with dimming is an incredibly robust ground connection. This goes for the connections made at the battery side (some people call it the "Big 3"), and the connection made at the amp side. Short and well-researched ground points that make a safe path back to the battery will result in less voltage drop due to less resistance in the path. Also, using oversized power wire will reduce voltage drop, as will a somewhat unorthodox method of "double-barrelling" your power wire. Explanation needed here... Say you have two amps that need 4 gauge wire. You could run 1/0 gauge to the back, then distribute 4 gauge runs from a fused block, right. Well, the other way to do it is to do two identical runs of 4 gauge to the trunk. This idea was presented to me by Stephen Mantz, owner of Zed Audio, maker of some of legendary amps. He suggested that a straight run to the battery is better than a distribution block, which may steal from one or another amp's power supply to equalize the voltage when a voltage drop occurs. Using straight runs (fused by the battery of course) of wire to the amps prevents this.

So, there's some things to consider for you.

 

This is why I love this forum. You get people willing to share expert advice, free of charge. Thanks fourthmeal for the clarification. Makes sense to me.