rossmer

OK finally got my 01+ radio adapter harness built and installed this weekend in my 99 GS3 and it worked first time! I've attached the exact pin-to-pin connections you need to make from the 70-1761 Metra harness to the 01+ plug. I got my 01+ plug from the junkyard so it had all the wires in the pins that I needed. You will need to move some of the wires in the Metra connectors to match the diagram. Hopefully the diagram is clear on pinouts between car side and harness side as this trips up folks sometimes.

Regarding connecting up Grom BT3 or USB2P, there is no way to keep the CD changer connected. It simply does not allow it. The CD audio plays over the Grom audio. After disconnecting the connector on back of CD changer, all was fine. I installed Grom BT3 for direct AUX input from my XM receiver and bluetooth for audio and hands-free calling. There are 2 cable options for the GS, the C-TOY1 or C-LEX cables. I stayed with the TOY1 cable as it attaches to the unused 12-pin connector on the back of the 01+ radio. The LEX Y-cable attaches to the 20-pin connector on radio and allows you to connect adapter harness you built into it. I tried both cables and each had the same result, not allowing CD changer to be connected. Hope this helps someone else.