vfield

I have created the attached graphic (.jpg) for others to use in hooking up after market stereo head units to the factory amp/speakers. I used a Metra 70-8112 connector to connect after market audio device to the installed wiring and audio components (AMP and speakers). This connector should be available in most after market car stereo stores. Unfortunately this connector does not accomidate factory sub woofer connection. That sub woofer audio connection is on another connector. (R1) Drop me a note if you need sub woofer info as I have not yet tackled that aspect of my project.
This works in my 1998 SC400 which origianally had Nakamichi unit with CD. I believe this info is good for any Nakamichi installation. I put +12v on Beep connector (#13) to turn on factory amp.

Jimbo2828

so let get this right. i can use this harness and a aftermarket deck and my stock amp and speakers will still work??? but what do i do about the sub then???

vfield

Jimbo
I see after revisiting the wiring manual I have incorrectly labeled the connector on my diagram as R3 (C), should be R4 (A). -- <Change to above diagram has been made>
Yes you can use this connector to connect an after market deck to the existing 4 channel factory amp. The woofer feed goes thru another connector, R2. This is a 10 pin connector and the woofer amp audio feed goes into pins 1 and 5. Appears that pin 5 is the (-) or ground.
Attached graphic should help clarify. I do not know of an after market connector for this plug. You will likely have to cut off the factory plug. Perhaps others know of a useable plug.?????