Goodman furnace: No LED Signal
Professional repair
Why is the diagnostic light off on my Goodman furnace? Per the Goodman service manual, an internal control failure or a blown board fuse will cause the diagnostic LED to provide no signal. It can also simply mean the board isn't getting power.
GOOD NEWS: THE FIRST CHECKS ARE FREE AND TAKE MINUTES.
Try these first — in this order
Check the breaker, door switch, and board fuse — about 10 minutes.
Before replacing a board, have a technician find what killed it (shorts often repeat). DIY part cost: $80–180 — a pro visit for this class of fault typically runs $150–350.
What causes it (in order of likelihood)
- Tripped breaker or blower-door switch not engaged (check first) DIY-CHECKABLE
- Blown fuse on the control board (official check item) DIY-CHECKABLE
- Failed integrated control board TECH
Parts referenced by this code
Always match parts against your model's parts list — part numbers vary within a series.
Applies to
GMS8 · GDS8 · GHS8 · GMSS96 · GMH8 · GDH8
Different Goodman generations use different code maps. If your series isn't listed, don't assume this meaning — check your blower-door label.
Verified against Goodman GMS8/GDS8/GHS8 Service Manual (RS6612006), p.42-43 — “will cause the diagnostic LED to provide no signal”
Last verified 2026-07-06 · how we verify