Goodman furnace 6 flashes: Rollout limit open, or control module fuse blown
On GMSS9 and AMSS9 boards, six flashes covers two faults of very different seriousness: a rollout limit open, or a blown control module fuse. The code cannot distinguish them.
- Rollout switch has tripped — Goodman GMS, GMH, GMV8, GMV9 and Amana AMH, AMV9 series gas furnaces with a single red diagnostic LED
Applies to: Goodman GMSS9 and Amana AMSS9 series gas furnaces with a single red diagnostic LED, where six flashes covers both a rollout limit open and a blown integrated control module fuse. On Goodman GMS, GMH, GMV8, GMV9 and Amana AMH, AMV9 the same flash count means rollout only. Goodman GMP has no six-flash code at all — its published table ends at five flashes. These boards report flash counts only and have no alphanumeric display codes.
What it means
This page exists because the same flash count means different things on different Goodman furnaces, and the difference is not cosmetic. On GMS, GMH, GMV8, GMV9 and AMH boards, six flashes means a rollout switch has opened — flame escaped the burner compartment, which is a carbon monoxide risk. On GMSS9 and AMSS9 boards, Goodman's own code database describes the same count as covering the rollout limit being open or the integrated control module fuse being blown. A blown fuse is an electrical fault of ordinary seriousness. Because the code cannot tell you which, the safe reading is the rollout case until a technician establishes otherwise. Note that these are flash-count boards: they have no two-character display, so a GMSS9 never shows an alphanumeric code such as E5.
Most common causes
- A rollout limit switch open, meaning flame escaped the burner compartment.
- A blown fuse on the integrated control module, usually caused by a short in the low voltage wiring.
- A blocked or restricted heat exchanger.
- A blocked or partly blocked flue.
- A failed or weak draft inducer.
- Dirty or misaligned burners producing unstable flame.
- A short in the thermostat or low voltage wiring, on the fuse side of this code.
How to diagnose it
- Confirm the furnace model before interpreting six flashes. GMSS9 and AMSS9 boards mean something different from GMS, GMH and AMH boards.
- Treat it as the rollout case until proven otherwise, since the code cannot distinguish them.
- Check that carbon monoxide alarms are present and working. If any has sounded, leave and call the fire service from outside.
- Note whether the furnace will restart at all, since a rollout switch requires manual reset and a fuse does not.
- Note whether the thermostat display is blank, which would point at the fuse side.
How to fix it
- Turn the furnace off at its service switch and call a licensed heating technician.
- Do not press a rollout switch reset button to restart the furnace.
- If the cause turns out to be a fuse, the short that blew it still needs finding — replacing the fuse alone blows the next one.
- Have working carbon monoxide alarms on every level of the home and outside each separate sleeping area, which is what NFPA 720 and US Consumer Product Safety Commission guidance call for. That includes the level the furnace is on — basements, attics and utility spaces are where a combustion fault starts, and an alarm only on bedroom floors can miss it for a long time. This fault is one of the situations those alarms exist for.
Notes
This is the clearest illustration on this site of why the model matters as much as the code. Six flashes on one Goodman furnace is a serious combustion fault; on another it may be a blown fuse. Reading a code without knowing the model is guessing.
Related
- 6 flashes — Rollout switch has tripped
- Reading a furnace fault code — How to find, count, and interpret the diagnostic light before looking anything up
All codes for this manufacturer
Goodman and Amana furnace fault codes — every code, with what differs between models.
Not sure this is your brand?
The same count means something else on other furnaces. What 6 flashes means on every brand puts them side by side.
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.
The same two faults, filed separately elsewhere
The GMSS9's decision to share one number between a rollout trip and a blown fuse has relatives and refuseniks. Goodman's own GMEC96 makes the same fold at five red flashes, while the communicating boards give the fuse its own honest code, E5. The rollout half's cross-brand family — the codes that mean flame left the burner compartment, full stop — is catalogued on the rollout switch hub. When a code can mean either a $5 part or a combustion event, knowing which your board is showing is worth more than any repair tip, and only a meter answers it.
What the fix costs
Two invoices could not be less alike. The fuse branch: $5–150 for the fuse plus the short-hunt per the control board cost guide, typically traced to a pinched thermostat wire or a slipped screw through insulation. The rollout branch starts at $150–350 for switch-and-cause work per the repair cost guide — but its cause list includes blocked heat exchanger passages, and heat exchanger findings on a single-stage furnace of this class are usually the moment the replacement conversation starts rather than a repair line item. Budget nothing until the technician tells you which page of this fault you drew; the two answers differ by two orders of magnitude.
DIY or call a pro?
Entirely professional, and the ambiguity is the reason: you cannot see from the LED whether you have the trivial fault or the combustion one, and only the trivial one tolerates casual handling. The rollout possibility sets the rules for both — no resets to see if it clears, no running the furnace to observe, because if flame did leave the burner compartment, every restart offers it another chance. Treat six flashes on this board as a furnace-off condition until someone with a meter separates fuse from rollout. The consolation: the test is quick, the fuse outcome is cheap, and the rollout outcome is precisely the situation where you will be glad the furnace spent the wait switched off.
What this looks like
From the outside, this usually shows up as the furnace heats then trips out on high limit — that walkthrough covers what to check in order, and when it stops being a homeowner job.