Error Code Green 1 Flash
Info

Goodman GMEC960803BN Error Code Green 1 Flash: Normal Operation - Low Stage Cooling (Ylo + G)

TL;DR
Your furnace blower is running in low-stage cooling mode. This is normal operation during air conditioning.
Disclaimer
This article is for informational purposes only and does not guarantee the accuracy or completeness of the information provided. Always turn off power and gas supply before attempting any repairs. If you smell gas, leave immediately and call your gas company. Consult a licensed HVAC technician for diagnosis and repair. Any actions taken based on this information are at your own risk.

What Does Code Green 1 Flash Mean?

A single green flash on the Goodman GMEC960803BN indicates the blower is running for a low-stage cooling call. The control board is receiving signals on both the Ylo (low-stage cooling) and G (fan) terminals from the thermostat, commanding the blower to operate at the speed configured for low-stage air conditioning.

The GMEC960803BN is a two-stage furnace that also manages blower speeds for connected air conditioning equipment. During low-stage cooling, the blower runs at a lower, quieter speed that matches the reduced capacity output of a two-stage air conditioner or heat pump. This provides more efficient, comfortable cooling during mild conditions when full capacity is not needed.

This is an entirely normal operating state. The green LED flash pattern simply confirms that the control board is receiving the correct thermostat signals and running the blower at the appropriate speed. No action is needed unless you notice that the home is not cooling adequately, which could indicate an air conditioner issue rather than a furnace problem.

Contact a licensed HVAC technician if any of these apply:

Sources

  1. *MEC96 & *CEC96 Two-Stage Gas Furnaces

✓ Verified against manufacturer service manual — March 2026