Hopefully that will work out for you then.
I've got about 180 of the terminal below (P/N: 12110843). This is a Female Metri-Pack 280 Tin Plated Terminal, Cable Range 0.50 - 0.35 mm2, Cable Insulation Range 2.19 - 1.47 mm.
I suspect you will need:
P/N: 12129663 for 3.0mm2 wire (12 AWG)
P/N: 12129424 for 2.0 - 1.0 mm2 wire (14 AWG - 16 AWG)
Depending on current, you may also be able to get away with a thin stock terminal:
P/N: 12110842 for 3.0 - 2.0mm2 wire (12 AWG - 14 AWG)
Anyway, thought I'd post this since I had already looked it up. This may not apply if your terminals aren't tangless. Terminals with a tang will have different part numbers.
You may be able to find these at your GM dealer. The service guys should likely have a toolbox looking item with about 5 red trays of terminals inside. I've sourced some terminals similar to these from them.