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HOW-TO: SC300/SC400 Install Aftermarket Head Unit, OEM Speakers and Sub Working!

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Old 08-13-12, 06:02 PM
  #376  
raine
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Originally Posted by kpkim01
Just putting my 2 cents in, but I have a nak in my sc and used the metro harness and it worked, ordered it off amazon. Maybe I got lucky idk but the only thing that does not work is the stock sub****
I wired an aftermarket sub/amp
LOL then technically it didn't work
Old 08-14-12, 08:16 PM
  #377  
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but i wonder if he simply cut the wire harness for the sub and hooked up an rca like you did would it worked. i'm guessing the reason it didn't work for him was he didn't have the sub wired.

the more important thing is if he suffered any ground noise from using the harness. that would tell us if the nak uses common ground without an issue.
Old 08-17-12, 01:33 AM
  #378  
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UPDATED 08-17-12:
- Revised wiring procedure for OEM subwoofer amp in section I; new wiring scheme allows head unit to power and have complete control of OEM sub amp and OEM antenna functions. The text/photos below have been incorporated into the original posts:


I. ANTENNA/SUBWOOFER AMP RECONFIGURATION


1. (sorry no pic) While your rear seats are still out, remove the 3rd brake light/subwoofer grille by pulling the leading edge upward to release the clips (don't yank it up - just pull up enough to release the metal clips) then slide the 3rd brake light/subwoofer grill towards the front of the car to release the hooks. Unplug the 3rd brake light for now.

2. (sorry no pic) With a little easing you can get the package shelf off, exposing your rear speakers, subwoofer, and the subwoofer amp (located between the right-rear speaker and the subwoofer.) You should now be able to access the subwoofer amp, which is recessed to the passenger-side of the subwoofer.



3. Locate the Subwoofer Amp harness:

Sub-Amp-Harness (G-Harness):
10-pin plug with 10 wires, 4 on top and 6 on the bottom, as shown below:



G-Harness Wire Color Guide
G1 black
G2 red with black stripe and silver dots
G3 blue with white stripe
G4 grey
G5 white
G6 blue with black stripe
G7 brown with silver dots
G8 brown with black stripe and silver dots
G9 black with white stripe and silver dots
G10 red with white stripe and silver dots

Here are the wires in the plug, and where to connect them:

G-Harness Connections
G3 to amp turn-on wire
G4 to amp turn on wire
G6 to amp turn on wire

4. First cut G3, G4, and G6 on the PLUG SIDE (the side nearest the rear window area) leaving about 3 inches of wire attached to the plug - don't cut the wires flush to the plug!

5. Now, splice together G3, G4, and G6 with the amp turn-on wire. See the diagram below for a clearer picture:





By the way, to get the amp turn-on wire (the 15-ft. wire you routed to the trunk along with the speaker wire extensions) from the trunk to the subwoofer harness, there should be a few open holes on the package shelf; use one of these holes to run the amp turn-on wire from the trunk to the subwoofer amp harness area.

These connections do three important things:
A. Allows your new aftermarket head unit to power and control the OEM sub amp.
B. Allows the sub amp to stay on regardless of which source you're using.
C. Allows the antenna to function normally - up when the tuner is on, down for all other sources.
Old 08-19-12, 05:28 PM
  #379  
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OK Nakamichi peeps...

I'm pretty sure I can get the procedure down for a Nakamichi setup, but I need someone with a Nakamichi system to help me with some info/photos. If I get the wiring right, I can add the Nakamichi info to this thread, so it's a complete write-up for BOTH systems.
Old 09-05-12, 08:21 AM
  #380  
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Originally Posted by kpkim01
Just putting my 2 cents in, but I have a nak in my sc and used the metro harness and it worked, ordered it off amazon. Maybe I got lucky idk but the only thing that does not work is the stock sub****
I wired an aftermarket sub/amp
I wired up a Pioneer X910BT in the SC last night with the Metra, but following all other instructions for antenna/sub. So more or less, used the metra to minimize my factory harness cutting . Antenna stays up anytime the HU is powered (regardless of input). The sub does not work (even with the RCA splice procedure and "Remote turn on" wire spliced into G3,G4, and G6 on the rear deck.

I have the wine as well (i was trying to avoid running the individual speaker wires to the back), so I'm going to redo the grounds and see if that fixes the issue. My rear right speaker is getting no sound, so hopefully its just the speaker and I can replace. If its the amp, then I have no choice but to run new wires to the trunk and do the amp bypass. What an adventure... but Raine... props for the writeup... I just need a bit of help to figure out the sub.
Old 09-05-12, 01:22 PM
  #381  
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Originally Posted by PJ
I wired up a Pioneer X910BT in the SC last night with the Metra, but following all other instructions for antenna/sub. So more or less, used the metra to minimize my factory harness cutting . Antenna stays up anytime the HU is powered (regardless of input). The sub does not work (even with the RCA splice procedure and "Remote turn on" wire spliced into G3,G4, and G6 on the rear deck.

I have the wine as well (i was trying to avoid running the individual speaker wires to the back), so I'm going to redo the grounds and see if that fixes the issue. My rear right speaker is getting no sound, so hopefully its just the speaker and I can replace. If its the amp, then I have no choice but to run new wires to the trunk and do the amp bypass. What an adventure... but Raine... props for the writeup... I just need a bit of help to figure out the sub.
Another Metra... C'mon people.

OEM setup is this:
OEM head unit, line-level signal --> OEM harness --> OEM amplifier, amplified signal --> OEM speakers

People who use the Metra harness as-is gets this:
Aftermarket head unit, amplified signal --> OEM harness --> OEM amplifier, amplified signal --> OEM speakers

See what's wrong there?

The output of the OEM head unit is line-level, because it sends the signal to the OEM amplifier at the trunk. If you don't bypass the OEM amplifier, you're sending an amplified signal into a line-level input - which usually blows things up, or causes new issues to pop up (like maybe your "bad speaker"). Your second problem is the ground, OEM system uses floating grounds for the OEM speakers; the Metra harness doesn't account for this. The whining noise most likely isn't from the head unit ground, but from the floating ground. Your third problem is that you didn't run the speaker wires so you didn't bypass the OEM main amplifier. Your fourth problem is related to #3 - your antenna stays on because you still have the factory amp in place and you didn't remove/bypass it as per instructions.

I've said it a million times - do NOT use the metra harness!!

Most people try to use it anyways to probably save time. You did to "minimize your factory harness cutting." and to "avoid running the individual speaker wires to the back" and in the end look where it got you?

No shortcuts. If you want it to work right then you have to take the time and effort and do the job right. GLHF
Old 09-05-12, 02:40 PM
  #382  
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Thanks. Rewiring now from the leftover monoprice cable i had left over from my boat's tower speaker install.
Old 09-05-12, 05:18 PM
  #383  
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Did the amp bypass. Like OP said, antenna works and now no more whine. I gotta stop being lazy.

Oh, and the sub...it was all ok as originally wired...the sub was unplugged from the amp... my orig problem

But yeah, the right rear speaker is still no good...more troubleshooting tomorrow.

Edit: Rear speaker was blown, picked one up for $5 at the j/y this am. All good in the neighborhod.

Thanks again Raine!

Last edited by PJ; 09-06-12 at 09:59 AM.
Old 09-09-12, 11:23 PM
  #384  
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Originally Posted by PJ
Did the amp bypass. Like OP said, antenna works and now no more whine. I gotta stop being lazy.

Oh, and the sub...it was all ok as originally wired...the sub was unplugged from the amp... my orig problem

But yeah, the right rear speaker is still no good...more troubleshooting tomorrow.

Edit: Rear speaker was blown, picked one up for $5 at the j/y this am. All good in the neighborhod.

Thanks again Raine!
Good to hear you have everything working

BTW If there's anyone with a Nakamichi system that wants to help me figure out how to get this How-To working for BOTH systems, shoot me a PM.
Old 09-16-12, 07:22 AM
  #385  
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Great write up, but where were you in 06 when i had to figure this out wire by wire...j/k
Old 09-25-12, 07:56 PM
  #386  
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raine,

this for putting this together. i just did this for my 99 with nak system. i opted not to buy the metra harness and i read other posting about this. they are 100% wrong.... your colors don't match the nak setup but the PIN OUTS DO WORK! only a couple of the colors work. The ant. color is the same. The power, constant, dimmer are different but pinouts are the same. Which completely make sense since there is only one metra harness for toyota with amp so therefore people said it works and therefore the pin outs can't be different.

I figured out an easier way to rerun the door speakers. Cut the wire at the kicker panel. If you follow the harness back, you'll see two wires. On the driver side it was the bottom two or top two on passenger side don't remember. (purple and pink) purple was ground. On passenger side it was blue and green. ground was blue. Then for the rears since you have to take everything down anyways go ahead and run new speaker wire to the front of the car. I'm putting in a 5 channel amp so running the rear wires wasn't needed and running the new speaker wire from the kicker panel is very easy.

Another cool trick that a stereo shop told me was to buy the GM ant. adapter. on my 99 the lexus comes with another antenna that is in the rear glass. with that antenna in there i disconnected the stock antenna and just used that one with the GM adapter. They sell them at autozone for only $10 bucks.

Thanks,
Sid
Old 09-25-12, 10:05 PM
  #387  
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Originally Posted by sidwin
raine,

this for putting this together. i just did this for my 99 with nak system. i opted not to buy the metra harness and i read other posting about this. they are 100% wrong.... your colors don't match the nak setup but the PIN OUTS DO WORK! only a couple of the colors work. The ant. color is the same. The power, constant, dimmer are different but pinouts are the same. Which completely make sense since there is only one metra harness for toyota with amp so therefore people said it works and therefore the pin outs can't be different.

I figured out an easier way to rerun the door speakers. Cut the wire at the kicker panel. If you follow the harness back, you'll see two wires. On the driver side it was the bottom two or top two on passenger side don't remember. (purple and pink) purple was ground. On passenger side it was blue and green. ground was blue. Then for the rears since you have to take everything down anyways go ahead and run new speaker wire to the front of the car. I'm putting in a 5 channel amp so running the rear wires wasn't needed and running the new speaker wire from the kicker panel is very easy.

Another cool trick that a stereo shop told me was to buy the GM ant. adapter. on my 99 the lexus comes with another antenna that is in the rear glass. with that antenna in there i disconnected the stock antenna and just used that one with the GM adapter. They sell them at autozone for only $10 bucks.

Thanks,
Sid
1. I have heard that the pin-out locations might be the same, but it's the colors of each pin-out (for the Nak) that I actually need, for all of the harnesses.


2. RE: front speakers - Like you said, "since you have to take everything down anyways" it's still easier to run all channels (front, rear, sub) to the rear amp harness. Sure - if you do it your way, that will work for the front... but what if (after you install the aftermarket head unit) you decide to run an aftermarket amp? Then you're STILL running front speaker wire from the cabin to the trunk. Which means you'll have to remove the rear seat again, and the kick panels, and the center dash, and the lower front dash panels, etc.

Do it my way and anyone who wants to upgrade to an aftermarket main amp later will have EVERY connection they need in the trunk (power / ground / turn-on / all four speakers) and won't have to take apart the interior panels or run wires again (for the fronts).


3. As for the antenna, you're talking about the diversity system. I didn't mention the adaptor because it is dependent on what head unit you have, some HUs have the right dual-output, some require an adaptor for both outputs, some need an adaptor for one of the two.

Last edited by raine; 09-25-12 at 10:12 PM.
Old 09-25-12, 11:44 PM
  #388  
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Originally Posted by raine
1. I have heard that the pin-out locations might be the same, but it's the colors of each pin-out (for the Nak) that I actually need, for all of the harnesses.


2. RE: front speakers - Like you said, "since you have to take everything down anyways" it's still easier to run all channels (front, rear, sub) to the rear amp harness. Sure - if you do it your way, that will work for the front... but what if (after you install the aftermarket head unit) you decide to run an aftermarket amp? Then you're STILL running front speaker wire from the cabin to the trunk. Which means you'll have to remove the rear seat again, and the kick panels, and the center dash, and the lower front dash panels, etc.

Do it my way and anyone who wants to upgrade to an aftermarket main amp later will have EVERY connection they need in the trunk (power / ground / turn-on / all four speakers) and won't have to take apart the interior panels or run wires again (for the fronts).


3. As for the antenna, you're talking about the diversity system. I didn't mention the adaptor because it is dependent on what head unit you have, some HUs have the right dual-output, some require an adaptor for both outputs, some need an adaptor for one of the two.
stock wires are too thin if you want to run a nice 100 watt per channel. every shop recommended atleast 14gauge wire for the speakers. The rears wouldn't take more than 5 min tops to redo. Plus if you plan on putting in an amp you have to take the dash out anyways to run the rca's. I ran 12 gauge for the front speakers and 14 for the rears. I looked over the wiring schematics and it appears the speaker wire colors are the same for both nak and pioneer. just the wires for the radio harness has different colors.

you have to take the rear seat out anyways if you want to put the aftermarket amp there. I've seen a lot of installs that put a small 5 channel amp there. really nice and hidden.

I was happy to see the diversity antenna. i already disconnected my antenna and the stations were ok but on my supra the diversity antenna worked great.

Thanks,
Sid
Old 09-26-12, 01:33 AM
  #389  
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Originally Posted by sidwin
stock wires are too thin if you want to run a nice 100 watt per channel. every shop recommended atleast 14gauge wire for the speakers. The rears wouldn't take more than 5 min tops to redo. Plus if you plan on putting in an amp you have to take the dash out anyways to run the rca's. I ran 12 gauge for the front speakers and 14 for the rears. I looked over the wiring schematics and it appears the speaker wire colors are the same for both nak and pioneer. just the wires for the radio harness has different colors.

you have to take the rear seat out anyways if you want to put the aftermarket amp there. I've seen a lot of installs that put a small 5 channel amp there. really nice and hidden.

I was happy to see the diversity antenna. i already disconnected my antenna and the stations were ok but on my supra the diversity antenna worked great.

Thanks,
Sid
Don't get me wrong - I get what you're saying about the aftermarket amp, wire gauge, etc. - but the thread does say "Aftermarket Head Unit, OEM Speakers and Sub" for a reason

and I agree, the SC's diversity antenna isn't that great... I actually disconnected it and just use the main motorized antenna since it pulled stations better by itself compared to the diversity by itself.
Old 11-15-12, 09:30 AM
  #390  
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Just wanted to say thanks for this how-to (and the one on how to re-use the factory bracket with the aftermarket dash kit). I've had an aftermarket stereo hooked up via the RCA's in the Metra harness for about 5-years, and just dealt with the wining noise since then. I finally had time to do this re-wire and it killed the noise. FYI I am still using the Metra harness (didn't want to hack up the factory harness) and everything works perfectly. I just ran new speaker wire from the HU to the trunk and used your great diagrams so I knew what wires to tap. Factory Sub is still hooked up via the Metra harness as I don't get any noise out of it as-is.


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