Ihave a coleman furnace in my home and the fan on the exhaust motor went to heck so I replaced the fan .after reinstalling the blower unit the burner will not ignite.I made sure that the blower was working but it still doesn't work . All it does is run for about 1 minute then stop. Could it be the small vacume switch that is attatched to the blower housing with two wires connected to it. And can I check it by jumping the two wires.the model # is gm905080b12up11g. Thanks for your help

Best thing to do is not to jump it but pull off the hose to the blower and see if that little whole is blowing or sucking. The gently blow or suck on the tube to make the pressure switch click while the fan is on sometimes those switches get stuck