Does your furnace fan run? If so, you can use your thermostat to turn your fan on. If your fan does not run, you will want to check the circuit breakers. If your circuit breaker is "ON" and you still can’t turn the fan on, check the disconnect box mounted outside. The disconnect box will be mounted near your condenser. After you’ve tried this and your fan still won’t run, you will need to make a service call.