GOODMAN DIAGNOSTIC REFERENCE SINGLE RED LED — FLASH CODES DOC GOODMAN-CONTINUOUS-FLASH

Goodman furnace: Reversed 115V Polarity or Poor Ground

Q: Why is the light on my Goodman furnace flashing continuously?

Reversed 115V Polarity or Poor Ground. Official: the 115-volt line polarity is reversed or the unit ground is poor. The furnace won't heat until wiring is corrected.

YOUR LIGHT: RAPID CONTINUOUS FLASHING — MATCH IT ABOVE

Professional repair

Why is the light on my Goodman furnace flashing continuously? Official: the 115-volt line polarity is reversed or the unit ground is poor. The furnace won't heat until wiring is corrected.

See what causes this code ↓ Get repair quotes near you

Line-voltage wiring — electrician or HVAC tech.

What causes it (in order of likelihood)

Hot/neutral reversed at the furnace or outlet TECH
Poor unit ground TECH

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.44 — “CONTINUOUS / Polarity of 115 volt AC / Poor unit ground”

Last verified 2026-07-06 · how we verify