Wiring an aftermarket head unit to an L w

Here is how I have connected my new Pioneer DEH-P980BT head unit to my 2004 LW300-2 with Advanced Audio. A1-A12 and B1-B12 are the wires on the GM wiring harness. I may have gotten a few of the colors on the car side wrong as some of them are rather subtle. I was not able to find a stock wiring harness that matched this configuration, so I just bought a Scosche GM10B and re-wired it to match. I used a very small "jewelers" screwdriver as a pin extractor. After removing the plastic pin retainers from the back of the connector, I aligned the screwdriver vertically and then from the pin side punched it through the small opening above each pin and then pulled the pin out from the rear, rearranged the pins, then re-installed the pin retainers.

I have the head unit sending high level (speaker level) audio directly to the factory amp over the speaker wires without using a high-low converter. The factory amp is apparently designed to accept high level inputs. The factory amp also takes care of the subwoofer output.

The A3 amp turn on draws just a few milliamps, so no worries. Everything seems to work just fine without connecting B6 amp ground. However, when connected to A12 it sinks 30-40 milliamps and the variation depends on the volume level. Is that a ground loop or what?

I didn't do anything with B4, dimmer, because my head unit doesn't have any way to utilize it. It can and does utilize B12, illumination, though not particularly well.

Wires by function

A1 - N/C
A2 - N/C
A3 - Factory amp turn on lead
A4 - N/C
A5 - N/C
A6 - N/C
A7 - N/C
A8 - Left Rear Speaker +
A9 - Left Rear Speaker -
A10 - Right Front Speaker -
A11 - Right Front Speaker +
A12 - Ground

B1 - 12V+ constant
B2 - 12V+ switched (ACC)
B3 - N/C
B4 - Dimmer
B5 - N/C
B6 - Factory amp ground
B7 - N/C
B8 - Left Front Speaker +
B9 - Left Front Speaker -
B10 - Right Rear Speaker -
B11 - Right Rear Speaker +
B12 - Illumination

Wires by color from the car side

A1 - N/C
A2 - N/C
A3 - Orange
A4 - N/C
A5 - N/C
A6 - N/C
A7 - N/C
A8 - Brown
A9 - Yellow
A10 - Blue
A11 - Green
A12 - Black

B1 - Orange
B2 - Yellow
B3 - N/C
B4 - Gray
B5 - N/C
B6 - Orange
B7 - N/C
B8 - Tan
B9 - Gray
B10 - Light Blue
B11 - Blue
B12 - Brown

Wires by color from the head unit side

A1 - N/C
A2 - N/C
A3 - Blue/White
A4 - N/C
A5 - N/C
A6 - N/C
A7 - N/C
A8 - Green
A9 - GREEN/ Black
A10 - Gray/Black
A11 - Gray
A12 - Black

B1 - Yellow
B2 - Red
B3 - N/C
B4 - N/C
B5 - N/C
B6 - N/C
B7 - N/C
B8 - White
B9 - WHITE/ Black
B10 - Violet/Black
B11 - Violet
B12 - ORANGE / White

Oops, the car is a 2004 Saturn LW300-2 with Advanced Audio.  I hope the info saves the next guy some time as none of the online resources I was able to find had correct info.