Carrier furnace rapid flashing: Reversed 115V Polarity
Professional repair
Why is my Carrier furnace light blinking rapidly? Official: line-voltage polarity is reversed — and the control blocks heating until it's fixed. (If the furnace is twinned, see the twinning-kit instructions.)
Before you touch anything: the six signs that mean stop troubleshooting and call a pro →
Line-voltage wiring — electrician or HVAC tech.
What causes it (in order of likelihood)
- Hot/neutral reversed at the furnace TECH
Parts for this code
No specific part number is verified for this code — it typically points at wiring, power, a blown fuse, or communication between components rather than one standard replacement part. If your diagnosis does land on a replaceable component, match its part number against your model's parts list before ordering.
Questions about this code
Why is my Carrier furnace light blinking rapidly?
Official: line-voltage polarity is reversed — and the control blocks heating until it's fixed. (If the furnace is twinned, see the twinning-kit instructions.)
How do I fix Carrier furnace rapid flashing?
This is wiring work; don't open panels or test voltage. Call an electrician or HVAC technician. Twinned furnaces have their own instructions.
How much does it cost to fix Carrier furnace rapid flashing?
Cost depends on where the reversed wiring is and how much correction is needed. Ask for a quote once the wiring fault has been located.
Applies to
58STA · 58STX
Different Carrier generations use different code maps. If your series isn't listed, don't assume this meaning — check your blower-door label.
Same control platform, same code: Bryant furnace rapid flashing · Payne furnace rapid flashing
Verified against Carrier 58STA/58STX Installation & Service Instructions (1106202L), p.37+46 — “RAPID FLASHING - Line voltage (115VAC) polarity reversed... will flash rapidly and prevent the furnace from heating”
Last verified 2026-07-06 · page updated 2026-10-03 · how we verify
Related Carrier furnace codes
These codes use the same status led — short + long flash codes system.