Quoted from jester523:
Embarrassingly enough, that seems like what I did. I'm looking back at the pictures I took, and I definitely soldered the left wires to the right EOS and vice versa.
Thanks! I'll re-solder tonight or tomorrow and post back if it fixed it.
I took a lot of pics, but as I tear things down, I feel like I need to take even more pics. It really helps.