When the blower motor makes a screeching or squealing sound, it likely means a bad belt is the cause. Belt-driven blower fans are common in older furnaces and wear down, stretch, and crack over time. If the belt is making noise, is slipping, or shows signs of cracking, it's time to replace it.It's still blowing out heat and air (for now), noise is consistent. Likely problem? Easy or difficult fix?