Furnace burner won't light (ignite), fan runs, but no ignition.
Furnace is a carrier cobra model# GB1AAV048111.

I couldn't find any info on that model number, but my guess is that the Hot Surface Igniter (http://homerepair.about.com/od/heatingcoolingrepair/ss/furn_electr_ign_4.htm) could be bad. If so, it is an easy and inexpensive fix.

Good luck,
WallyH