C wire thermostat assistance
I had the same issue. All the instructions i found said connect one of the unused wires to the C terminal on the furnace and to the C terminal on the stat. Problem for me was there was no C terminal. I finally found a thread that was specific to my brand and it said connect the furnace side to the chassis. I had already come to the same conclusion after studying my wiring diagram but had continued looking just to be sure. I Did that and it works fine.