Hi I have a Nordyne E2EB-015/split unit A/C 5ton. I installed a new thermostat this weekend (marked all wires and replaced them to their proper location) The new thermostat is looking for a "C" or common wire. I have 3 wires that are not being used and the opposite end of them (at the air handler) are not connected at all. Where is this "C" wire to be connected? Thanks in advance.