Why Is My Aircon Louvre Not Moving?
A stuck louvre can be a swing motor fault, a linkage jam, or a command path issue. Each looks similar from the room but requires a different fix. The flap behavior and sound pattern narrow it down.
1. Swing Motor Response Fault
How This Works
The swing motor in the indoor unit is a small stepper or synchronous motor that receives a drive signal from the indoor PCB and rotates the louvre flap through a defined arc. When the motor weakens, from worn windings, degraded capacitor, or a shaft that has seized slightly from years of continuous cycling. It can no longer generate enough torque to move the flap against even light resistance. The flap stays parked at whatever angle it last held, or jitters through a fraction of its travel before stopping.
How To Tell
If the swing motor is the fault, the flap sits completely still or jitters through a fraction of its arc. It does not catch at a consistent point. Cooling continues normally, which is the key contrast with a control path issue where other command functions also behave erratically. If the flap fails to start at all from any swing command, test motor voltage output at the terminals before considering the PCB.
- Cooling can still be normal while the flap stays in one angle.
- Small clicking or jitter sound comes from the flap area.
- The flap may move a little, then stop or return to the same position.
How We'd Confirm It
We test swing motor voltage output and rotation response to confirm the motor itself is failing before replacing it.
Replacing the motor first can fail if the linkage is the real problem.
2. Linkage Jam Or Movement Obstruction
How This Works
The louvre flap sits on a pair of pivot pins and is linked to the motor shaft through a small plastic arm. Over time, particularly on units in rooms with cooking fumes or high dust, the pivot pins accumulate sticky residue that stiffens their rotation. A cracked or warped linkage arm can also cause the flap to bind at a specific angle in its travel range. When this happens, the motor receives the command and begins to drive, but cannot complete the arc. It stalls partway and the controller either holds or abandons the position.
How To Tell
A linkage or pivot fault causes the flap to stall or catch at the same angle every cycle, not fail to start entirely. This is the clearest contrast with a swing motor fault, which prevents movement from the beginning. Unlike a control path issue, only the swing movement is affected; all other remote commands respond normally. Check whether the flap moves freely by hand without resistance before electrical diagnosis.
- Flap movement looks uneven or catches at one point.
- The sound pattern repeats at the same flap position.
- Swing command appears to trigger but full movement does not happen.
How We'd Confirm It
We inspect the flap rail, pivot points, and linkage arm for cracks, warping, or debris that restrict movement.
This often gets misread as a board problem when the fault is mechanical movement.
3. Control Path Issue Causing Repeated Drive Attempts
How This Works
The indoor PCB governs the swing motor through a dedicated output channel that pulses with a controlled drive pattern. When this signal path becomes unstable, through a degraded PCB component, a corroded motor connector, or a wiring fault between the board and motor, the controller may send repeated incomplete commands. Each attempt partially drives the motor, which then stalls or reverses, creating a fast clicking or chattering pattern at the flap. The flap assembly absorbs this mechanical stress on every failed cycle.
How To Tell
A control path fault produces repeated, incomplete drive attempts, the flap chatters or clicks rapidly rather than sitting still or catching at one point. Unlike a swing motor fault, the motor is receiving erratic commands, not a clean signal it cannot respond to. Unlike a linkage jam, the movement attempts are random across the arc rather than failing at a fixed position. Other command functions may also behave inconsistently at the same time.
- Flap movement attempts repeat without a stable response.
- Clicking grows louder or more frequent when swing is triggered.
- Other command functions may also behave strangely at the same time.
How We'd Confirm It
Stop forcing swing commands and let us check the indoor PCB swing output signal and wiring continuity to the motor.
Manual forcing of the flap can damage the linkage and make diagnosis harder.
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