"Unhooked the wire going to the gate of my FET's"
Floating Gate.
The Gate needs to be at 0V or 12V-ish. If it is not, then it sort of 'leaks' and gets hot.
If disconnecting an N-fet Gate, it should be connected to 0V (battery negative, or Source).
Do the fets have a high Ohm resistor from the Gate to Source? I was thinking yours did.
It should have been enough to keep the fet solidly shut off.
G-