If you still haven't figured it out, try connecting your remote input to your power cable at the amp. Just hook up the positive, negative, and remote. It should power on.
If not, test the wire with your continuity feature on the multitester. Disconnect the power wires and hook up another wire temporarily to the end and run it back to the other end, and use the multimeter there. I just have a hard time believing your cables are dead, especially the 2 ga. It'* probably a connection, or bad remote turnon signal/wire.