Blowing cold air can be a sign of trouble with a heater blower and a troubled thermostat. Therefore, follow the steps to troubleshoot it.
Check thermostat settings: Check the thermostat settings and switch the heating modes to activate the heater and fan as needed.
Check the filters and vents: Dirty filters and clogged vents restrict the airflow, so it is better to clean and replace the parts whenever needed.
Call professionals: You have to assess the situation first and call heating services Glendale, CA, for expert services.