I have a mgha-077abfc-01 furnace. The pilot and burners fire. The blower will start and run for about thirty seconds then shut down but the burners continue to fire. This cycle will continue until I turn the unit off.
Is there a limit/ safety switch that may be causing this.

Sounds like a fualty fan control. Follow the wires back from the fan motor and see where you are losing power. How old is your furnace? Can you post a couple pics if the inside controls on the unit?

Thanks I am unable to send a picture as the unit is not at this location. I will look into the fan wiring at a latter date. Thanks