The Echo is up and running, new (junkyard) alternator, and new plugs and fresh oil has it sounding like a new car. Might do a coolant flush and maybe transmission flush, but for now it’s fine to drive.
Whoever wired the stereo is an idiot. Previously, there was some aftermarket head unit that the previous owner took out. I had this wise idea to “oh, I’ll just put in another aftermarket stereo” only now I see the harness in the Echo is different than the Toyota standard one and doesn’t match the ones I have for the new radio!!
I have no clue what these wires do.