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Discussion Starter #1
I'm going to soon be installing an Alpine 7897 headunit along with my stock NAV.

So far my search has only turned up some lukewarm info on how to do this. I hope to be documenting my install as a reference for those who may try this in the future.

http://www.is300.net/forum/viewtopic.php?t=13323234&highlight=nav+headunit
http://www.is300.net/forum/viewtopic.php?t=13309064&highlight=nav+headunit

For those of you who have an aftermarket HU and stock NAV (undertow, JDM_SXE-10, TahoeSSDVD, siliconboy, SeattleIS300), could you please chime in and post as much info as you know firsthand. I know most of you had it done by a professional installer but try to contribute any details you know.

The concensus seems to be that the stock NAV requires the presense of the stock HU to operate. Which wires/connections in particular need to be maintained? Anyone out there with an aftermarket HU that doesn't have the stock HU present??
 

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Discussion Starter #2
For reference:


 

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I had an Alpine CDA-7894 Installed, we had to put the Stock HU in the trunk and ran what I believe to be just speaker wires to the back of the trunk connected to the Stock HU. The Installers (My cousin and friend) also unplugged 1 plug from the Factory AMP and have left it unplugged. I can take pictures of the plug that is unplugged but have no idea which one it is by description and I can also take a picture of the Stock HU and it's connections in the back. Now I have tested other HU to see compatability and I have found that the JVC SH Models work really well, and very easily with our (my) setup. I currently have a JVC SH-707 (MP3 was a must) and the HU auto dims with the Headlights / Dash lights, it also mutes when the navigation comes on, so voice guidance is easier to hear (exactly like stock). Both things the Alpine CDA-7894 did not do for me.

I will ask my cousin to give me alot more insight and I will reply to this topic again with more appropriate information. If you do want any pics let me know, of what and I'll get them taken ASAP. Also, my next project is to hook up an XBOX to the Stock Navigation, so I'll have a Game System and a DVD Player for the Nav Screen. I'll let you guys know how that goes in the coming weeks after Christmas.

Hope this helps a little

Kevin
 

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Discussion Starter #4
Keven,

Pictures would be great! Especially the ones you extended to the trunk for the stock HU. Anything else you can add would be greatly appreciated.

Also, I'm confident that the Alpine 7897 model has a dimming funtion. Crutchfield says that the 7894 model you had also supports dimming. Hopefully the 7897 will also have a cell phone mute function. I intend to have everything working just as you have your JVC setup. Did you run the NAV guidance through a seperate small speaker under the dash?
 

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TeCKis300, No other speakers were needed, the nav still runs of the small tweater in the drivers door pillar. I will go take pictures of the Stock HU in the back, the connection to it and the Unplugged Plug and come back and post. Also, yea the Alpine 7894 had a mute wire, and an auto dimming function, but for some reason they would not work properly. I could manually dim the radio rather easy so it wasnt a big deal, and also the Nav interuppted the front speaker so I could hear the nav, just no one else in the car could really since the other speakers stayed at normal volume. now with the JVC they all mute, and the front tweater goes completely silent with music, so the nav can speak through (Like Stock)

Be back with pics.

Kevin
 

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Ok Pictures have been taken. Here are some direct links to each picture.

Picture of the JVC HU with Stock Navigation On and Working:
http://photos.yahoo.com/bc/undertow69/vwp?.dir=/2002+Lexus+IS300&.src=ph&.dnm=JVC+KD-SH707+with+Nav+On.jpg&.view=t&.done=http://photos.yahoo.com/bc/undertow69/lst?&.dir=/2002+Lexus+IS300&.src=ph&.view=t

Picture of the Unplugged Plug, View #1:
http://photos.yahoo.com/bc/undertow69/vwp?.dir=/2002+Lexus+IS300&.src=ph&.dnm=Factory+Amp+Plug+Unplugged+1.jpg&.view=t&.done=http://photos.yahoo.com/bc/undertow69/lst?&.dir=/2002+Lexus+IS300&.src=ph&.view=t

Picture of the Unplugged Plug, View #2:
http://photos.yahoo.com/bc/undertow69/vwp?.dir=/2002+Lexus+IS300&.src=ph&.dnm=Factory+Amp+Plug+Unplugged+2.jpg&.view=t&.done=http://photos.yahoo.com/bc/undertow69/lst?&.dir=/2002+Lexus+IS300&.src=ph&.view=t

Picture of the Stock HU Padded in the Trunk with Wire Running into it:
http://photos.yahoo.com/bc/undertow69/vwp?.dir=/2002+Lexus+IS300&.src=ph&.dnm=Stock+HU+padded+in+the+Trunk.jpg&.view=t&.done=http://photos.yahoo.com/bc/undertow69/lst?&.dir=/2002+Lexus+IS300&.src=ph&.view=t

Picture of Stock HU with Back Connections:
http://photos.yahoo.com/bc/undertow69/vwp?.dir=/2002+Lexus+IS300&.src=ph&.dnm=Stock+HU+back+connections.jpg&.view=t&.done=http://photos.yahoo.com/bc/undertow69/lst?&.dir=/2002+Lexus+IS300&.src=ph&.view=t

* The Picture with the Unplugged Plug has ONLY the Brown, Grey and Blue/Yellow wires still connected, ALL other wires have been cut (As shown in the picture).

Hope these help and lemme know if you need more specific pictures.

Kevin
 

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Discussion Starter #7
Nice...that was quick.

A few more questions...

Are you using the stock amp to run any speakers?

If you are not, are you using the HU to drive the speakers or an external amp?
 

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Im using the stock amp, I have no external amp and have added no additional speakers. basically unplugged that one plug in the back of the Stock HU (shown missing in the last pic) and ran just those 3 wires to the stock HU and used everything else stock.

I'll ask my cousin tonight for any technical info, or info I just simply dont know, or can't comprehend.

Kevin
 

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Discussion Starter #9
Undertow,

Is that the Scoche or Metra kit you have installed?
 

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This should only be related to keeping the NAV working with no stock HU. For those who don't have a stock NAV, you all don't have to worry about any of this crap :)

Now, I concede that you can tap the low level inputs of the factory AMP and use that AMP/speakers, but do you need the factory HU hooked up still? There are conveniences to this approach since the front and rear speakers are wired seperately (ugh) and a rewire from the new HU is a pain in the ass.

There's a low level "harness" available, but is it based on the stock Toyota amp? Toyota's with the 6-CD changer have a seperate amp (2000 and later made by Panasonic), and the HU plug is exactly the same as the IS300's, but I don't know if the wiring is the same. The amp is not the same, though (by sight).

But again, my installer didn't have time to keep looking for the "magic" combo without keeping the stock HU, which is of course, in the rear of my S/C. In the end, I'm happy (listening to "Chrome" on XM radio) :)

--sb
 

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it is definately possible. I had my stock deck relocated to the trunk, and little work went into maintaining functionality. I thought it was going to be a nightmare, but the installer had no problem with doing it.

any good shop can do it.
 

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Anyone aware of how to keep the nav working without the presence of the stock amp, because I lit mine on fire last night. Any help would kick ass, because I have a 1,000 dollar fucking nav system that exists only as a paper weight.. Been cracking at this shit for two days, and I am no closer to a solution.

Kill
 
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isekii
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