I have a Goodman GMP075-3. Woke up this morning to 60 degree house. Thermostat set to 68. Clean filter, batteries in thermostat are good. Can turn FAN on and it runs, but cannot get heat to kick on. Red blinking light on board. Power to unit. Draft fan never kicks on, never see ignitor glow. Gas valve on. Have shut down entire unit and let "reset" for 5 minutes, and still nothing. Suggestions?