Are luxaire furnice fires up than the gas shuts off and blows cold air,turnit off and on the switch on it might work right sometimes. Ireplaaced the ignighter aand it did not make any diff.

Clean the fame sensor with some fine sandpaper.

My Gas Luxaire furance will not heat and the blower will not stop. I have to turn off the blower.

Sounds like it is out on limit, or a flame role out switch. This will cause the blower to run all the time.