Success! Sorry in advance, as this post is gonna be a bear (and no real pictures either), but for those like me who want an easy to follow guide to install a stereo, I think this will be worth it...
Simple Cheap Stereo Install (w/Amp Bypass)
Parts-
-$90 Miratowa TH0011 (
https://a.co/d/fyZzQMe)
-$10 Metra 70-8112 Harness (
https://a.co/d/hpfkXlL)
-Assorted Butt connectors, wire screws, and wire taps
-Wire cutting/crimping/stripping tool
-10mm wrench
-14mm wrench
Time required- 2 hrs, mostly spent splicing connections at an easy pace. Less if you've done it before.
Here are the only two references I needed to make this happen, aside from the bag the Metra harness came in and the startup guide for the Miratowa head unit. The first is from the site mentioned in the beginning of this thread, and the second is from this site-
https://tlcfaq.com/main/2012/05/land-cruiser-lx-470-stereo-wiring/
View attachment 3308584
View attachment 3308585
Step 1.
Build the Harness.
Modify the Metra harness. Because you're not using passive RCAs to the amp, youll have to clip the RCAs off and splice the Metra harness to the Miratowa harness. Remember that shared ground on the RCAs is the Speaker Ground (S GROUND), so all the negatives (FR-, FL-, RR-, RL-) will splice to that. Everything is super easy because the colors match between the Metra and Miratowa harnesses. Best part is that you can do this indoors with some beers and take your time.
The only issue with the Metra harness that I found is that it doesnt have a spot for ILLUM. You'll have to tap that guy (Pin 9) on install later, or be like me and just say screw it!
Step 2.
Amp Delete.
Remove the amp and jumper the power for your headunit as well as the speakers.
Amp removal- there are two forward 10mm bolts (one which you'll want to return as it's an anchor for a ground), and two aft 10mm bolts hidden under a foam block. Remove all the bolts, disconnect the connectors, and boom- amp gone!
Jumpering Connections- There are two connectors; S7 (little guy, comes from the headunit), and S6 (big guy, pushes signal to speakers).
First splice all your power connections.
On Connector S7 remove pin 3 (B+ out) and on Connector S6 remove pin 7 (B+ in) and butt splice them blue and gold bad boys.
On Connector S7 remove pins 2 (accessory in) and 9 (accessory out) and splice em together.
On Connector S7 remove pin 10 (ground int) and on Connector S6 remove pin 13 (Ground out) and splice em!
That's all your power splices. Now for your speaker splices.
Front Right- On Connector S7 remove pin 6 (yellow) and on Connector S6 remove pin 1 (yellowish green). Splice em!
Front Left- On Connector S7 remove pin 5 (pink) and on Connector S6 remove pin 2 (pink). Splice em!
Rear Right- On Connector S7 remove pin 14 (red) and on Connector S6 remove pin 3 (red). Splice em!
Rear Left- On Connector S7 remove pin 13 (white) and on Connector S6 remove pin 4 (black). Splice em!
Speaker grounds- On Connector S7 remove pin 11 (black). This is the speaker ground. Hold onto this guy for a second. On Connector S6 remove pins 8, 9, 10, and 11 (purple, blue, white, and yellow- all the ones that were directly underneath what you just spliced). All these guys will get spliced together to the speaker ground.
I know. That was a lot of splicing, and this is supposed to be simple. It is! This is as simple as it gets with the LC.
Step 3.
Install the stereo.
This is the easy part. The center dash just pops off. I used the brackets from the side of the OEM headunit to mount my new one.
Now that you have everything spliced under the passenger seat and the harness spliced together and ready, you literally just have to put it in, plug the harness into the headunit and the P500 connector (the only one that fits the harness).
Step 4.
Add Options.
There are a ton of optional components you can add to the mix here before you button up, or later when you decide to do the work. I'll try to cover what I can think of.
-Backup Camera/Forward Camera
I'm not going to run through a full backup camera install, but instead remain focused on the headunit side of the install.
On install if you decide to add the backup camera, you'll have to tap the Reverse signal from the ECU behind the glove box.
Forward camera requires no such tap, but will require you running the feed in through the firewall. A good place is right in that same area, behind the ECU.
-Antenna
The LC uses one standard mast antenna and a second antenna in the rear window glass. The standard power antenna is plenty powerful and uses a normal connector, but if you really want to connect up that rear glass guy as well just to get a bit more reception range, you'll need an antenna splitter and an mda b adapter.
-Microphone
The main reason I installed this is to get better call quality while driving, so a microphone was an essential upgrade for me. I mounted mine on top of the steering column- putting it close to me but out of the way, and not in a place where it will be affected by breeze from the windows or AC.
-Sub
You'll note I didn't wire in the stock sub. That's honestly because it's rather anemic and frankly I dont like how it's tuned (totally personal preference). Instead I have ordered an underseat powered sub which I'll install where the stock amp used to sit under the passenger seat. Several folks have had luck with them, and the largest I've been able to find record of having been installed was approx 10x13x3.5, although I believe you could grab a bit of space and bring that up to about 10x16x4, depending on how good you are at clearancing space in that spot. That said, anything that big would really be pushing your luck.
As for routing, it's just a quick run of RCAs from the back of the headunit to the sub, and then tap into the power and grounds that you spliced first thing earlier. If it needs a remote on signal, you can grab that from Connector S7 pin 1.
Hope this helps someone else! Not gonna lie- with all of this info in various places across the internet I was super nervous to tackle this, but if I had been able to use a reference like this early on I probably would have done it weeks ago. Cheers!