If your furnace isn’t turning on, it’s important to check if the thermostat is malfunctioning. To determine this, you can try a few troubleshooting steps: - First, make sure the thermostat is set to heat mode and that the temperature setting is higher than the current room temperature. - Next, check if the display on the thermostat is functioning properly and if it’s receiving power. - If these steps don’t solve the issue, it may be time to call a professional for further assistance.