MistyS

Great article. I really learned a lot from it.


Now, this maybe a too-dumb question to ask. But this is the first time I opened up my car and tried to install some major changes. So, please forgive me.


My question is why do we need to run wires or cables through the side door under the carpet. Can we simply run them though the center. If necessary I can run a plastic pipe or something through it and hide the wires inside. Would that work?


Thanks very much if you are still helping anyone.

motorheaddown

Great question! It's really a matter of preference. I installed an aftermarket amp and used the existing wiring in the car because it's more than adequate. Or, you can run them down the center; however, you might have to pull the carpet out to lay them in.

Others install their own wires down the kick panel. Here's a great write-up by CL member "raine" on installing an aftermarket head unit: https://www.clublexus.com/forums/lex...b-working.html

Thanks,
-scott

MistyS

Thanks for the help, Scott. Yes, I watched that write-up already. It is really good.

YG300SC

im having a problem finding the [amp turn on wire]. My head unit only has the following P.CNTR, P.ANT. I tried both of these and followed every step to the T. I got all the other speakers to work except the Sub woofer. help plz

ThatSCguy

Hey Raine,

I'm looking at the pioneer FX-720BT

It already has a built in amp and I plan on using all oem speakers so my question is would I still need to connect to the amp below the cd changer and what not, well to use any of the oem amps to begin with?


**Update** I just read Section D. Thanks Raine, great write up!!

KahnBB6

iTrader: (5)

Raine, thank you for this!

I have a question if you or anyone familiar can help:

On Page 1 in the diagrams you say that Pin A11 should connect to a ground wire. Is this wire coming from the main body harness a ground wire from the factory... or is this just for the purposes of this DIY? In other words, is this wire what Toyota specified for the Pioneer stereo headunit to ground itself? And if so (coming FROM the Pioneer head unit side) could that wire theoretically be grounded to the chassis and not into the body harness?

Thank you if anyone can help!

I am actually not doing this mod as described. I have taken the "do not use this" Metra harness and a Metra OEM repair harness to create a patch harness for use WITH my original stereo in the service of another device. Essentially this is a pass through harness I am making, however on the "do not use this" Metra harness side, pin A11 is missing.

Again, Raine, I know you do not like these harnesses but please forgive my odd question-- I'm doing something different. In my case I'm keeping my OEM Pioneer stereo have made a patch harness. I'd love to ground this A11 wire from the Pioneer head unit side if that's all it is. Otherwise I need to source another one of these to get a spare terminal lead.

Thanks!

raine

iTrader: (7)

First of all - sorry previous posters if I didn't answer your questions, for some reason i wasn't getting the email notifications from the forum for awhile. But I am now.

Second - in response to your question: my notes say that it's the factory ground connection for the head unit. If you don't have that wire in the vehicle side of the harness, then I suppose you can just ground your head unit directly to a chassis bolt behind the radio area.

KahnBB6

iTrader: (5)

Raine,

I've only just now seen your response. Thank you!

What I found out was that no matter where I tried externally grounding Pin A11 coming from the Pioneer I was unable to get rid of interference noise. Pin A11 ground back into the factory A11 pin on the body harness ended up being crucially needed for the factory Pioneer headunit to function without high pitched interference noise.

I tried buying another of the Metra body harness-side harneses to steal a pin... only to discover that the company used to use Toyota style pins but has now moved to something generic that still works with the connector it is designed to fit into! I had an older Metra harness from about 2012 which uses the Toyota style pins.

I then went through a PDF of all the Toyota repair pin/electrode types for the SC300/400 and I found the identical one needed for the older style Metra.

82998–12410 "Toyota Non-Waterproof Spade"

And that did it for Pin A11. I soldered the pass-through connection and voila-- I had a patch harness for the stock stereo that retained all correct function and sound. I should note that I took apart the RCA connector section that doesn't work with the stock amp and rewired that to be a straight pass-through along with everything else.

For anyone who doesn't happen to have a Metra breakout harness made around 2012 or earlier the Toyota pin trick probably won't work. You just need to buy two of the current ones in order to make a patch/pass-through harness and steal a single pin from one of them to fit into the other.

I got that far but unfortunately once I plugged in the connection to for the auxiliary device and used a chassis ground for that--a Popformance LXCC HVAC touchscreen controller-- I had zero issues with the aftermarket device but I unfortunately got electrical ground noise in my Pioneer on all channels no matter where I tried re-grounding on the trans tunnel. Leaving the LXCC harness unplugged while the Pioneer was on with the patch harness attached presented perfect audio once again.

Talking to the designer of the LXCC he suggested that the Pioneer was just never designed for this kind of ground noise isolation.

So in short... I'll likely be reusing this pass through harness I made in order to follow your guide instructions to install an aftermarket stereo after all. The Pioneer is apparently very finicky and any newer aftermarket headunit is apparently going to be better designed to isolate and remove ground interference noise.

I know this presents a really oddball left field use of this guide since the point of it was to do the opposite of what I did concerning the factory stereo but maybe the information can be of help to someone for some reason.

To that end, if it can, or to just make visual sense of this post, here's a link to the thread page detailing some pictures of what I did:

https://www.clublexus.com/forums/sc-...ml#post9339683

Raine, thank you again! I couldn't have tried my crazy idea without your guide in the first place!

raine

iTrader: (7)

Actually, after all that what you found was:

And back to the very first post:

Don't say I told you so, lol. But okay - going back to what you described, the only part about what you typed that stood out to me was:

What??? LOL
The fact that the noise only comes out when the LXCC is plugged in tells you something - either it's getting some ground looping by being close, or the LXCC kicks out some ground noise of its own when it's plugged in and powered on near the head unit. I looked into that LXCC thing just now real quick, looks like the LXCC thing is encased in plastic... not saying this is what's happening, but plastic doesn't shield noise like metal. It's possible that the added ground noise you're hearing through the audio may actually be coming from that LXCC thing. Sounds like they're trying to pass the blame on the Pioneer. Whatever

No problem. BTW you paid $430 for that LXCC thing? $400 could have been put towards a nice new head unit. $30 for the dash kit LOL

KahnBB6

iTrader: (5)

Huh?

No, in this case (although it took some work and hunting for an additional pin) after taking a Metra harness for aftermarket stereos, completely dismantling the wiring and combining that with yet another Metra type harness meant to *repair* SC300 Pioneer stereo connections back to stock and directly merging each pin point between the two... it did work. It worked in the sense that it became a patch-harness while retaining my stock Pioneer stereo which is what I'd wanted in the first place. With the LXCC turned off it was just fine.

If I had been attempting to connect any type of aftermarket stereo I completely agree that it would have been obvious that you can't trust Metra's setup because you detailed that very, very clearly in the beginning of this thread. And when I do go aftermarket, I fully intend to follow the exact procedure you've given us. I might still use the Metra connector to avoid cutting my original factory one but you can bet I will only do so by checking that every single wire corresponds to your guide. And changing any wire connections that don't. I'm okay with the extra work involved. But I would only trust the connection methodology you have laid out in this thread.

You've got no argument from me that as Metra *designed* their harness to just be plugged in with no additional modification for an aftermarket stereo... it absolutely does not work. And used for an aftermarket headunit OR in a fully custom scenario... one has to be willing to get into wiring by following your instructions and completely ignore whatever wiring is on the Metra and change/solder whatever is necessary in order to have the convenience of not cutting the stock harness.

This was different. I didn't change any wiring locations from stock. I just extended them all.

Raine, your warnings weren't lost on me. But again, I completely dismantled and disregarded the bad wiring of the Metra harness and simply made an extension/patch harness for the stock head unit. I was not trying to use it to hook into an aftermarket stereo. I checked every wire connection against the pinout before using it.

I know well enough that IF someone is going to bother with using any of these Metra harnesses for anything on the SC you have to be willing to tear into it and follow your instructions to completely check that every pin is doing what it should.

...Or else just don't use the Metra harness at all and cut into the stock harness. I wanted something to avoid cutting and just plug into. But I was under no illusions that the Metra, for ANY application would "just work".

For the purposes of newcomers coming to this guide on the first pages, I completely understand dissuading them from bothering with any Metra harness at all as it adds unnecessary complication to the main instructions which can be achieved without it anyway.


^^ This tells me something new, thank you! Yes, it's encased in plastic, however so is the original SC300/400 HVAC controller front. I completely agree that if noise is created as a result then plastic won't shield anything. I'll look into that.

It's not just possible that the added ground noise is coming from the LXCC-- It was definitely coming from the LXCC as I had it hooked up according to the instructions. Unplug the LXCC and the noise stops and the patch harness introduced no abnormal noise or function.

The patch harness I custom made with the LXCC disconnected has zero ground noise or distortion. Plug the LXCC in again and I get a constant high pitched ground noise problem no matter where I've grounded.

I've also recently read somewhere that noise contamination might also be possible by sharing the same Battery/Constant +12V connection wire. I'm really not sure if that holds water. I've taken the rest of the LXCC connection troubleshooting back to its regular thread as this is as far as I want to go with deviating from the original focus of yours.


I did. I wanted the virtual engine gauge function it has without cluttering up the original look of my interior with many physical gauges on the windshield pillar, etc. I can't recall any aftermarket headunits having built-in support for up to eight 0-5V programmable gauge inputs of my choosing. OBD2 readouts maybe but my car and the GTE swap I'm building are both OBD1.

Just because a head unit is brand new doesn't automatically impress me The LXCC on the other hand, did impress me with its functions and layout.

I'm very underwhelmed by just about every new head unit I've researched from all the big companies and several smaller ones. Few to none of them come close to matching the SC's interior or have a reasonable aesthetic look.

If they're double-din touchscreen units they have UI's with too much stuff in them that I'll never use (installing "apps" on a car stereo system doesn't appeal to me). The UI interfaces are often not very well thought out.

That's just me. I like buttons and dials and a clean look. I'm not looking for much other than sound quality. That's why, at the end of the day I've been quite happy with the stock Pioneer once I added the aux jack mod and plugged a hardwired bluetooth module into that behind the dash. It may be old but it does exactly what I want it to.

All I've been able to find that I do like for quality and looks to replace the stock stereo are basically old hard to find Nakamichi 1-Din units from several years ago: CD-400, CD-500, CD-700II and MB-VI.

Believe me, I'd LIKE to find a brand new head unit that fits the bill but it's not an easy task.

Raine, I'm very glad for your advice and this thread guide. I know my goal and approach here is an odd one. I have my reasons for sticking with the factory head unit (thus far). I originally just wanted to ask your advice with a couple of pins which more or less exceeded the main scope of the DIY but that's been solved now anyway.

I posted my last reply with details of my results only in case it might be of help to anyone applying similar logic. I was not trying to in any way advocate that a Metra SC300/400 harness should in any way be used as it was intended by Metra. If that's how my earlier posts came across then I apologize for the confusion-- that wasn't what I had intended.

raine

iTrader: (7)

You know, after I replied I was thinking about the post more and I thought "wait... why was he using a Metra harness with the OEM Pioneer?" - I guess that explains it.

The original HVAC is in plastic too, but it's just a simple LCD that doesn't constantly "move" things on the screen like that LXCC thing. So who knows (?) - but maybe the LXCC needs its own power source isolated from the OEM stereo.

There is truth to the "sharing the same 12v+" statement... especially when you're dealing with amp draw. For example, in car audio speak if you were to run a 10-foot 4-ga. cable from the battery to a high power amplifier (for example let's say it draws between 40-60-amps), then splice in a smaller 10-ga. 12v+ power line between the battery and amp for a smaller electronic device (let's say a processor that draws no more than 5-amps at normal operating voltage), when the amplifier needs the power, that affects the other device (that doesn't ever draw the same amount as the amp). So in this example, if the amplifier is pulling 60-amps, part of that 60-amps is still passing through the smaller 10-ga. wire. All that amperage is exceeding what the processor normally is supposed to "see", thus that causes electrical noise and can cause issues with the processor.

Hey, everyone has their own wants and needs. If you like the OEM head unit's look, that's perfectly fine - It's your car, so it doesn't matter what other people think. But keep in mind that you're working with/around a 90's era OEM head unit that features a cassette and a non-standard 1.6-DIN size designed to output a split floating-ground signal to the OEM amplifier. If you really want to hear sound quality, you should hear what a simple single DIN $400 head unit with aptX Bluetooth streaming sounds like

No worries. I didn't think that at all. If anything, it's better to ask than assume, right?

KahnBB6

iTrader: (5)

Yep That's why I was saying it wasn't at all a normal (however ill-advised) use of the Metra harness.

This is a good point. Although the JDM Soarers did have an option for the EMV touchscreen stereo/HVAC center stack. But I'm sure the wiring harness for those models must be very different from USDM Pioneer & Nakamichi harnesses. Plus, since those were CRT's there must have been a bit more shielding than what a normal SC or Soarer's stereo center would have.

^^^ That stands out to me as VERY significant. I'll bet that has something to do with the noise issue I've been getting. And it is a stereo system that was never designed with shared power source wires in mind.

At least for the Pioneer I think this may be the way to get it right. However at this point I think I may decide to go aftermarket after all since the noise isolation will probably be much better in a modern head unit.

That said, I won't bother unless a new head unit looks good in the car.

I don't mind the cassette deck although mine isn't working any longer and I'm not going to go out of my way to get it fixed. Really it's just the OEM look, the simplicity and that the only features it didn't already have that I need were aux-in and wireless bluetooth.

It is an old dinosaur. No arguing that.

I did find one brand new Single-DIN head unit I liked from a visual aesthetic: Pioneer Stage 4 DEX-P99RS. But it's horrendous at $1200+ and it looks like it was designed specifically for a full custom system. Even price aside it would be overkill for the stock SC amp and speakers.

Looks great though! Why does it take over $1,000 to get a new single din that looks decent?

Absolutely! I like getting the facts straight but I always like to try out original approaches with those facts if they suit an idea I like. Whether or not the approach works in the end is part of the risk of experimenting.

raine

iTrader: (7)

At this point I would suggest to just go full aftermarket - it's just less headache, better sound, and more modern features. Plus think about it - you're spending a whole lot of time trying to make a 2 decade old (depending on model year of course) head unit still work. And in the end once you figured it all out and get all the bugs worked out... congratulations, you still have a 2-decade old stock head unit.

Stage 4 is Pioneer's high-end competition level stuff. It is designed for a full custom system, and the $1200 price tag is normal in car audio. Hell - my current head unit (Kenwood DNX-892) was $1200... but it has all the features I wanted: 7" touchscreen, DVD, SD, HDMI, built-in Garmin GPS, DSP, time-alignment, dual USBs, aptX bluetooth audio, even an auxiliary switch. But that's my taste. Your requirements/visual taste/budget may vary.

In reality, if you were to budget that same $1200 to upgrade, that would cover a mid-range single DIN, a set of mid-level components for the front, and a small amplified sub. This setup is fairly entry-level as a whole, and it won't wake the neighbors up - but it sure as hell will blow away the factory audio in the SC on any day.

Honestly, like I mentioned above - in this day and age I wouldn't waste too much time with the stock audio in the SC. It's 90's technology. In fact, I only did the head unit how-to because at that time money was tight. But again - it's 90's tech, and we are in 2016.

The stock SC audio system isn't worth the effort to try to fix. It sucks. LOL

KahnBB6

iTrader: (5)

And... the two-decade old stock head unit is actually what I'd be happiest with, to be honest. I wouldn't be considering an aftermarket stereo if I didn't likely need one to eliminate electrical connection noise from the LXCC unit or any other custom gauges (like plain looking VDOs) or engine control or monitoring electronics that might get added later.

To me (and I am well aware I'm in the minority here) the stock head unit already looks invisible, is very easy to use, quick and easy to read, non-confusing, non-distracting, has *****, has great AM and FM reception (yes, I do actively use AM while on road trips for the amusement factor) with the factory aerial antenna and all it took to bring it up to modern usefulness was the aux-in jack mod and an aftermarket hard-wired Bluetooth audio / phone module hidden behind the dash.

And the fact that it was designed for the look of the dash and is capable of lasting as long as it has is also appealing to me. But then again, this isn't my first classic car even if the SC is young in that category.

I completely understand that 90% of Lexus SC owners will want a modern deck or a touchscreen with all the latest features and that this makes me an exception.

That's what I thought it was for, thanks. But it does look very, very nice from a visual standpoint. I'd probably be happy with a $150-$400 1-DIN that looked *exactly* the same. But nothing does, of course, even in Pioneer's own lineup of otherwise extremely ugly 1-DIN HU's.

I looked up that model Kenwood. That one actually looks decent. And having a built-in Garmin map system for those times when you're in the middle of nowhere on trips outside of good cell reception effectively replaces a travel Garmin for the same purpose.

My visual taste and budget does vary from yours in this area but you have nice taste!

Yeah, it's really old but it's an impressive old stereo in stock form. It looks a hell of a lot better than many old original car stereos from the 60's-90's. And it holds up. To me a "crappy" original stereo (for lack of sound quality and sometimes looks as well) is what you'd find in a 60's VW Beetle or 80's Dodge, Ford or GM. Between examples like those and the SC stereo I don't think there is a comparison.

It's a toss-up for me. I'm already happy with the stock audio system sound quality so long as it works. I even found a new in box factory sub-amp a couple of months back to replace my old blown one simply because it was easier to do that than to re-engineer the car's audio setup. A couple of years ago I replaced the rear deck speakers with a couple of Polk Audio 4" units after the stock ones failed. Again... all because I just needed the stock system repaired to normal function.

The CD changer in the trunk doesn't play CD's but as long as it allows the "CD Err" screen so I can have a dedicated clear aux-in channel it does what I need it to.

This is just me, and I am NOT knocking you or anyone who enjoys modern or custom car audio. It's a fascinating and cool area. But personally, budgeting $1,200++ on a stereo system upgrade for my car is far less appealing than spending the same amount towards getting my sequential twin turbos or GTE cylinder head rebuilt for installation.

I may have to go aftermarket stereo to get the LXCC or another gauge setup to work but I'm the exception to the rule here. To me the factory HU and system still looks, works and sounds great. Less or sparse features (beyond having Bluetooth audio/phone and aux-in) on an HU is actually more my thing.

Anyway... if I determine that an aftermarket HU is the only way to go to solve the other issue then I'll update the result here in the thread. But it might be little more than an old 2000's era Nakamichi or $100-$150 Clarion 1-DIN HU if I do

raine

iTrader: (7)

Yeah... 80's GM OEM stereos were so bad.

Like I said dude - whatever floats your boat. You don't have to explain why you prefer the OEM stereo, all I was saying is that for the sound "quality" (90's quality) it offers it's not worth the trouble. But by all means, if you want to keep the OEM then that's fine, you have your reasons.

Plus, an SC isn't a classic. At least not the one we got here in the U.S. Heh