Goodman furnace solid green: Standby — powered, no call
A steady green light means the furnace is powered, healthy, and waiting. If the house is cold and the light is solid green, the furnace has not been asked to run.
Applies to: Goodman GMEC96 and Amana AMEC96 two-stage gas furnaces with a three-colour diagnostic LED.
What it means
Green on this control indicates cooling and standby states, and a steady green is the idle indication: powered, no faults, no call. That is genuinely informative when the house is cold, because it narrows the search considerably — the furnace has power, its safety circuits are satisfied, and it has no stored fault. It simply has not been asked to do anything. The request comes from the thermostat over the low voltage wiring, so a cold house with a solid green light points at the thermostat, its wiring, or its power rather than at the furnace itself.
Most common causes
- The furnace is idle and everything is normal.
- The thermostat is not calling for heat — set to cool, set to off, or set below room temperature.
- The thermostat's batteries are flat.
- A break in the low voltage wiring between the thermostat and the furnace.
- A thermostat that has failed or lost its programming.
- A thermostat wired incorrectly after replacement.
- A zone control board not passing the call through.
How to diagnose it
- Check the thermostat is set to heat and above the current room temperature.
- Replace the thermostat batteries if it takes them, even if the display looks normal.
- Note whether the thermostat shows a call-for-heat indicator. A thermostat that thinks it is calling and a furnace showing standby means the signal is not arriving.
- Check whether the blower runs on the fan-on setting. Fan working and heat not points at the heat wire.
- Note whether the fault followed a thermostat replacement, since miswiring produces exactly this.
How to fix it
- Correct the thermostat setting or replace its batteries.
- If a thermostat was recently changed, have the wiring checked against the furnace terminals. Smart thermostat installations without a common wire are a frequent source of no-heat calls.
- Low voltage wiring faults and zone control problems are technician work, though they are among the less alarming findings.
- If the furnace is heating normally, nothing needs doing.
Notes
Knowing what your own furnace shows when idle is worth the minute it takes to look. A solid green light means nothing useful if you do not know it was solid green last week too.
Related
All codes for this manufacturer
Goodman and Amana furnace fault codes — every code, with what differs between models.
Models this code appears on
From the manufacturer's per-model database. If your model is not listed, this code may not exist on your board, or it may mean something different — check the model page.
Related signal patterns
More signals like this across brands: normal operation signals.
What the fix costs
Solid green is the cheapest thing this furnace ever displays: powered, no fault, waiting. It also quietly rules things out — the transformer, the board's power path, and the stored-fault list are all fine, or the LED would say otherwise. So a cold house behind a solid green light is nearly always a missing call for heat, and the money follows the thermostat circuit: batteries (yours, nearly free), a thermostat replacement at $150–400, or low-voltage wiring work, all reached through a $75–150 diagnostic that is typically credited against the repair (repair cost guide). Gas-side repairs are simply not on this page's menu — the furnace has not been asked to do anything yet.
DIY or call a pro?
Start at the thermostat: heat mode, setpoint above room temperature, fresh batteries. Those three cover most solid-green-but-cold calls and touch nothing dangerous. The handover point is the wire: chasing a broken or shorted low-voltage run through walls and the furnace's terminal strip is technician work, and shorting terminals while probing is how the board's fuse blows and a non-fault becomes a dead-looking furnace. One more homeowner contribution — confirm the LED stays solid green when you raise the setpoint. If it changes, the call is arriving and the story is different; tell the dispatcher which happened.
What this looks like
From the outside, this usually shows up as there is no heat but nothing looks obviously wrong — that walkthrough covers what to check in order, and when it stops being a homeowner job.