I have a goodman central heating unit that's about 7yrs old. I turned it on for the first time this season and it won't blow any hot air so I cleaned the flame sensor with high grit (265) sandpaper and it still short cycles. Also the only error the error light gives me is a solid red with no flashes. Does anyone have any ideas?

What's the model number of the furnace? Do the burners ignite?