Error Code LED Steady On (Continuous)
Info

Goodman GMSS960803BN Error Code LED Steady On (Continuous): Normal Operation

TL;DR
A steady (non-flashing) LED on the Goodman GMSS960803BN means the Integrated Control Module has run its self-checks and found no faults. No action is needed.
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 LED Steady On (Continuous) Mean?

The GMSS960803BN uses one diagnostic LED on its Integrated Control Module to report status. When that LED is steady on — lit continuously without blinking — the board has completed its internal self-checks and found no fault in any monitored circuit. The furnace is either actively running a heating cycle or standing by in idle, ready to respond the moment the thermostat calls for heat.

Because this is a single-stage furnace, there is only one firing rate, so a normal status here simply means the ignition, pressure-switch, limit, flame-sense, and polarity circuits all read good. It does not indicate how hard the furnace is working, only that nothing is wrong.

One point of confusion is worth clearing up: a steady LED is not the same as the continuous rapid flash that signals reversed polarity. Steady on is a solid, unchanging light; the reversed-polarity indication is a fast, repeating blink. If your light is actually flickering quickly rather than holding steady, read that as the reversed-polarity condition, not normal operation.

What You'll Notice

How This Is Diagnosed

There is nothing to repair here, but you can confirm the reading is genuinely "normal." Verify the light is truly steady and unchanging rather than a fast repeating blink, which would instead be the reversed-polarity indication. If the LED is steady yet the home is not warming, the issue lies outside the control board's monitored circuits — check the thermostat mode and setpoint, its batteries, and whether supply registers are open, since the board reports no fault in any of those external items.

Contact a licensed HVAC technician if any of these apply:

Frequently Asked Questions

My Goodman GMSS960803BN light is solid but I still have no heat — why?

A steady LED means the control board sees no internal fault, so the problem is likely outside the board's monitored circuits. Check the thermostat mode and setpoint, replace low thermostat batteries, and confirm supply registers are open before calling for service.

What is the difference between a steady light and a continuous flashing light?

A steady, unchanging light is normal operation. A continuous rapid flash is a fault code on this furnace indicating reversed electrical polarity, so the two look different and mean opposite things.

Should the diagnostic LED be on all the time?

Yes. On the GMSS960803BN the module keeps the LED lit whenever it has power and detects no faults, whether the furnace is heating or idle, so a steady light around the clock is expected.

Sources

  1. Installation Instructions for *MSS9* & *CSS9* Single-Stage Gas Furnace

✓ Verified against manufacturer service manual — March 2026