Hi,

I think I may have left info. Out. It's a gas furnace. The furnace unit is indoors... attachted to an outdoor A/C unit outside due to the central air... all attached to an automatic thermostat.

The furnace is NOT blowing any heat. It's just cold air. I've tried to reset it, checked the fuse. What else can I check?

Explain what happens when you turn the thermostat to call for heat, and what happens after that if anything does happen.