I recently bought an 02 Trailblazer LTZ. The radio was removed. The radio is still with the vehicle but not hooked up. The larger of the 2 wire harness has been cut out and is gone. I purchased a reverse wire harness and have been attempting to get that wired so I can use the original head unit. I have been trying to figure out how to wire this harness, but the wires in the dash don't match what I have found online. Here are the wire colors that I have: 2 orange, light green, dark green, orange w/ black, tan, 2 black, black w/white, brown, 2 brown w/white, dark blue.
Any help you can give to identify these wires would be greatly appreciated.

The smaller harness was not cut.
Bose system