Furnace blower comes on but the flame won't come on just runs waiting for ingnition of flame gas is on but it won't fireup I have lightly sanded the carbon off the lighter no change didn't c anything on anyway single mom tryn to fix it seems like something simple it was acting up before just had to manually flip power on unit couple of times it would start up then flame would lite everything fine until we left for while and the would reach its temp setting and then would not start its self now it is not lightning at all just the blower wants to run Please help I feel its simple I am alil bit of fix myself kind of girl but I am stumped and don't want be stupid and mess it up or get hurt very little cash flow doesn't help the situation either!!