OEM Lennox Blower Relay — 66C67

The genuine OEM Lennox 66C67 is an electromechanical relay that switches power to key components such as the blower motor, fan, or auxiliary loads in compatible Lennox furnaces and air handlers. Acting on a low-voltage signal from the control board or thermostat, it closes its contacts to energize the connected component at the correct point in each heating or cooling cycle, ensuring reliable, properly timed operation.

As the 66C67 relay wears, its contacts can pit, stick, or burn, leading to a blower that won't start, runs continuously, or cycles intermittently. You may also hear chattering or clicking from the control area, notice inconsistent airflow, or smell a faint burning odor from overheated contacts. These symptoms often mimic motor or board failures, making the relay an important part to verify.

Selecting a genuine OEM Lennox part ensures the relay matches the exact coil voltage, contact rating, and switching load of your Lennox system. Undersized or mismatched aftermarket relays can weld their contacts, overheat, or fail prematurely under load. The factory-matched 66C67 delivers dependable switching, correct fit, and the long service life your Lennox equipment was designed around.