Might have a bad capacitor or blower motor, or control board. Check to see if board is sending voltage to the motor.
I wouldn't get a board yet. Sounds like a dirty flame sensor. I don't know of any way to test the sensor, it only has one wire so there's no way to read across it. The way it works is the flame sensor is charged with AC voltage, that voltage converts to DC when it passes through a flame. Your board senses DC voltage and if it sees any DC voltage it knows there must be a flame. What tends to happen is that sensor gets dirty & doesn't pass enough voltage to the board.I had jumpered R to G (Fan ON) and there is no voltage across white to any of the three wires. Also continuously checked on auto after flame on for more than 30 secs - no voltage. I guess the board is history. Forgot to check: but if the three amp fuse on board is burnt than i suppose there would be no power (no red light)? A stupid quest: How much and where can I buy a board in Toronto? Again thanks a lot for the reply.