My furnace started blowing cold air, failing to ignite the gas. The red light on the circuit board flashes 4 times indicating faulty limit swtches. roll out switches tested good and the high limit switch was replaced but didn't solve the problem. Removing the fuse and the red wire from the thermostat temporarily with the power still on and the furnace will ignite after awhile, sometimes I need to jiggle the wires and circuit board to get it to start. Do I need a new circuit board? I have had a repair tech. here 3 times and as to date and has put in parts that were not needed. This furnace was installed in mid 2003 and not put into use untill 2004 due to heating ductwork. The owner of the heating service passed away and the business closed. The part number on the circuit board is PO31-01267-001 {cansi}. I would like a price and availability for the board please; any help would be appreciated - thank you.