Fujitsu Mini-Split Code 3A
Soft lockoutShown as: OPERATION lamp blinks 3 times, TIMER lamp blinks 10 times, ECONOMY lamp blinking continuously
Indoor unit communication circuit (wired remote controller) error. The indoor unit sees an abnormal remote controller group configuration, or cannot find the primary remote controller.
Manual wording: “Indoor Unit Communication Circuit (WRC) Error - When the indoor unit detects the configuration of the remote controller group is abnormal or the indoor unit detects lack of primary remote controller.”
Documented for: RGLX, RL2/RLS3/RLB/RLXB wall mounted with UTY-series wired remote controllers
Likely causes, most common first
- Disconnected or shorted cable between the wired remote controller and the indoor unit, or between indoor units
- Failed wired remote controller (indicated when 12 VDC is present at controller PCB connector CNC01)
- Failed indoor controller PCB (indicated when 0 VDC is present at CNC01)
What you can safely check yourself
- Turn the power off at the breaker for about 5 minutes and back on to see whether the code clears
When to call a technician
Diagnosing this requires metering 12 VDC at a board connector inside the indoor unit. A technician must do that.
A Fujitsu mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- 410A Mini-Split Troubleshooting Guide (Part # 6-26-FG2020 Rev. 5/2019) (Fujitsu General America, Inc., All R410A Halcyon mini-splits: RGLX, RL2/RLS3/RLS3H/RLS3Y/RLB/RLXB/RLXEH wall mounted, RLF/RLF1 multi-zone indoor units, RLXFZ multi-zone outdoor units, RML/RMLQ, RULX/RSLX universal-mount, RCLX cassettes) · checked 2026-08-25