OEM Lennox Flame Sensor Lead / Wire — 64L99

The genuine OEM Lennox 64L99 flame sensor lead is the high-temperature wire that connects your furnace's flame sensor rod to the ignition control board. It carries the tiny microamp flame-rectification signal that tells the control board a flame is present, allowing the gas valve to stay open. Built with heat-resistant insulation and the correct terminals, it provides a clean, low-resistance connection in the high-heat environment near the burners.

Common failure symptoms: A worn or damaged flame sensor lead can interrupt the flame signal even when the sensor rod is clean. Watch for short-cycling where the burners light then shut off after a few seconds, repeated ignition lockouts, flame-sense fault codes, and brittle, cracked, or burnt insulation on the wire. Loose or corroded terminals at either end produce the same intermittent shutdowns.

Why OEM matters: The 64L99 uses insulation rated for the temperatures found at the burner assembly and terminals sized to grip the sensor and control board precisely. Generic wire can melt, add resistance that weakens the delicate flame signal, or fit loosely, causing nuisance lockouts and no heat. Choosing the OEM lead ensures dependable flame detection and safe, uninterrupted furnace operation in your Lennox equipment.