Goodman GMEC960803BN Error Code Amber 3 Flashes: W2 Present With No W1
What Does Code Amber 3 Flashes Mean?
Three amber flashes on the Goodman GMEC960803BN control board mean the control module is receiving a W2 (second-stage heat) signal from the thermostat without a corresponding W1 (first-stage heat) signal. In normal two-stage operation, W1 must be present before or simultaneously with W2 — receiving W2 alone is an invalid signal combination, and the furnace will not operate.
This condition almost always points to a thermostat or thermostat wiring problem. The most common cause is thermostat wires connected to the wrong terminals, which can happen after a thermostat replacement or during initial installation. A faulty thermostat that sends incorrect signals can also produce this code.
The furnace itself is not damaged by this condition. Once the wiring issue is corrected so that W1 accompanies any W2 call, the furnace will resume normal operation. This is not a DIY repair because it requires understanding HVAC thermostat wiring conventions and testing individual circuits.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Improperly connected thermostat wires | Most common | ✗ Call a pro → |
| Faulty thermostat | Common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- The furnace will not heat and shows 3 amber flashes
- You recently installed a new thermostat and the furnace stopped working
- The thermostat wiring appears correct but the code persists
✓ Verified against manufacturer service manual — March 2026