The BLUE wires just send a 12 volt signal to the furnace to ACTIVATE the furnace to heat. Once the Blue wire sends the 12 volt signal the Fan relay is energized and the motor should come ON. NOTHING will happen until the Fam motor runs. So, you need to jump the 2 blue wires AT the furnace, not at the Tstat. Also, ONE of those blue wires must have 12 volts positive. So, IF you have no 12 volts at either BLUE wires that is the start of your problem. The blue wires start at your furnace and the Furnace supplies one of those Blue wires with the required 12 volts. It makes no difference which blue wire has the 12 volt power, just one of them. Doug
