I asked and asked. Nobody had answers.

Went to the local install shop and went through all of the install books.

Found the following adapters to use to make all of your connections and bypass the factory amp without cutting, or wire taps.

Metra 70-2003 GM 1998-UP adapter plugs in directly to the 04+ G35 Sedan Bose plug at the amp. Coupes may be different. The plug even clicks into the factory plug just like it would plugging into the amp. Now I just need to swap a few wires around on the plug to get the right pinouts.

To convert from speaker-wire to RCA use a Scosche FD03B pull the connectors out of the Scosche harness and plug them into the spots for the signal coming from the HU in the Metra Harness.

I will post pics when I am done fabricating the harness, but it should be a very clean install that I can quickly return to stock when the car needs service.

Thanks,
Pete

 

Forgot to mention, if you just want a way to splice into the factory harnes and keep the factory amp use a Metra 71-2003-1 combined with 70-2003 to give you a male and female plug that will go directly into the harness then to the amp.

Pete

 

You're the man! Nice work.

 

This works for the front and rear speakers (the ones by the back passenger seats) only. I would love to find a plug for the "subs" (the 6x9s in the rear deck). That connector is the white one with 6 connections in it. Right now I'm using some pins from an old connector to plug into this but would love a real connector. Anyone seen a compatible one? If anyone can answer this, I'll give them a cookie.

 

The sub channel is generated by the amp, so there is no pre-amp subwoofer channel in any except for the 03 sedans (and maybe some early 04s), which had a mini amplifier attached to the subwoofer

 

This plug (the one I mentioned) is for the 6x9s in the rear deck. The owners manual refers to them as "woofers" I am not using them as "subs". Sorry for any confusion.

I'm amplifying them using an aftermarket amp connected to an aftermarket receiver. I'm not even using the rear seat speakers just the front speakers and the rear deck (woofers) speakers (aftermarket). I use this plug instead of running separate wires from the amp so if I need to go back to stock I can just plug this back into the bose amp I took out.