Mr. FiXiT

[BullNBear52]

It's the igniter. When the thermostat calls for heat the blower comes on first to remove any residual gas fumes. At the same time electricity goes to the igniter to get it hot enough to ignite the gas. If you have any steel wool you can clean the igniter and see if that will then fire the gas. Carbon build up is often a problem. If that doesn't work then you need to replace it. S/B less than $100 when you're all done.