Heil Furnace Static Switch

ronnyd

I have a heil furnace that quit last night. The static switch is not letting power go through it. This static switch has 2 vaccum ports on it. One goes to the exhaust fan and the other goes to the fire chamber and is T'd to the gas valve. I can jumper the static switch and the furnace works fine. But when I hook it back up the furnace quits. The exhaust fan is working good I have good preesure outside. The vaccum line have been blown threw so they are clean. I can also get the furnace to work on a single line static switch with out the other line hooked up. What does the extra line do?