HVAC Code Lookup

York Furnace LED Steady Off

WarningShown as: No LED activity at all

The control board LED is not flashing at all, which means the board is not getting power or its on-board fuse has blown.

Manual wording: “LED STEADY OFF - If the LED light does not flash at all, check for power to the board and check for a blown fuse on the board.”

Documented for: TG8S, TG9S, TM9E, TM9V, TM8Y, TM9Y

Likely causes, most common first

  1. No power reaching the control board
  2. Blown fuse on the control board
  3. Failed control board

What you can safely check yourself

  • Check the furnace breaker in the electrical panel is on
  • Check the furnace service switch (the light-switch-looking one near the furnace) is on
  • Make sure the furnace door panel is fully seated - a loose door opens the door switch and kills power to the board

When to call a technician

If the breaker and switch are on and the door is seated but the LED is still dark, the fuse or the board itself needs a technician. Replacing a blown control-board fuse means finding what shorted it out first.

A York furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Sources

Other York codes