Amana AMSS920803BN Error Code No LED Signal: No 115 Volt Power / No 24 Volt Power
What Does Code No LED Signal Mean?
On the Amana AMSS920803BN, a completely dark diagnostic LED is different from every flash code. The board only produces flash patterns while it is powered, so when the light shows nothing at all, the message is that the Integrated Control Module itself is receiving no 115-volt or 24-volt power. In effect this is the absence of a code rather than a specific fault.
This single LED normally glows steady when the furnace is healthy (code-on), blinks a numbered pattern to report a fault, or flashes rapidly and continuously to warn of reversed polarity (code-continuous). A dark LED points upstream of all of those indications: to the household breaker, the furnace disconnect or blower-door safety switch, the low-voltage transformer, or the board's own small automotive-style fuse.
By far the most common causes are homeowner-checkable: a tripped circuit breaker or blown household fuse, or the furnace on/off switch or blower-compartment door being open. A blower door that is not fully seated opens a safety switch that cuts power to the whole board. Only in the uncommon case where power is confirmed present does an internal board or transformer fault come into question.
What You'll Notice
- No lights at all on the control board when you look through the sight glass or open the access panel
- The furnace does nothing on a call for heat — no inducer hum, no blower, no ignition
- A thermostat powered from the furnace transformer may show a blank screen
- The furnace was recently serviced, or a panel or blower door was removed and not fully reseated
- The furnace breaker at the electrical panel looks tripped or sits in the middle position
Common Causes
How to Fix It: Restore Power to the Furnace
What You'll Need
Steps
- Turn off power at the breaker and shut off the gas supply before inspecting Before opening or handling the furnace, turn the furnace circuit breaker to OFF at your electrical panel and turn the gas shutoff valve to the OFF position (handle perpendicular to the pipe). If you smell gas at any point, leave immediately and call your gas company from outside the home.
- Confirm the furnace on/off switch is ON The furnace has a standard toggle switch that looks like an ordinary light switch, mounted on or near the unit. It is easy to flip off by mistake. Make sure it is in the ON position.
- Fully seat the blower-compartment door A safety switch on the blower door cuts all power to the control module whenever the door is open, which makes the LED go dark. Push the lower access door firmly into place so the door switch is depressed.
- Reset the furnace circuit breaker At the electrical panel, find the breaker labeled for the furnace. If it is tripped (resting in the middle), switch it fully OFF and then back ON. If your panel uses cartridge or plug fuses, check for a blown furnace fuse and replace it with one of the same amperage.
- Restore power and watch the LED Turn the gas valve back ON, turn the furnace switch ON, and switch the breaker ON. Within a few seconds the diagnostic LED should light steady. Set the thermostat to call for heat and confirm the furnace begins its normal sequence.
When to Call a Professional
Contact a licensed HVAC technician if:
- The breaker trips again immediately each time you reset it
- The LED stays completely dark even with the switch on, the blower door seated, and the breaker reset
- You find scorched wiring, a melted connector, or a burnt smell near the control module
- The board's small onboard fuse blows again after it is replaced
Frequently Asked Questions
My furnace has no lights at all — is the control board dead?
Not necessarily. A dark LED usually means power is not reaching the board, most often from a tripped breaker or an open furnace switch or blower door, rather than a failed board. Rule those out first before assuming the module has failed.
Why does my furnace shut off completely when I open the door?
A safety switch on the blower-compartment door cuts power whenever the door is open, so the LED goes dark. This is normal — the furnace runs only with the door fully seated.
There is a small fuse on the control board — can I just replace it?
The board uses a small automotive-style fuse, but a blown board fuse usually signals a wiring short elsewhere. Replacing it without finding that short can damage the board, so that diagnosis is best left to a technician.
Sources
✓ Verified against manufacturer service manual — March 2026