Liftmaster RSW12U RSW12UL RSW12VDC Gate Parts
LiftMaster RSW12U, RSW12UL & RSW12VDC Replacement Parts
Genuine LiftMaster replacement parts for the RSW12U, RSW12UL and RSW12VDC residential swing gate operators — the 12 VDC pad-mount swing operator that drives the gate through a two-stage gear reducer and a cludge arm. All three share the same chassis, motor, gear reducers, arms and e-box; they differ only in the control board and the cover.
Which generation do I have? Open the e-box and read the main board:
K1D8389-1CC → RSW12U / RSW12UL (current UL325 generation)
K1D8059-1CC → RSW12VDC (pre-UL325)
Covers differ by generation. RSW12U takes the K77-37854 kit, RSW12UL the K77-39430 kit, and the RSW12VDC uses K77-37332. The bare cover is K75-36294-1, or K77-37856 in grey.
Straight or uphill gate? Ref 4 splits two ways — 75-50293 is the standard arm assembly, K75-50292 is the swivel arm for uphill or offset installations.
Not a swing operator? The RSL12 family is the slide-gate equivalent and shares almost no parts with this model.
Common RSW12U Repairs
| Symptom | Usual cause | Parts to check |
|---|---|---|
| Gate runs on mains but dies in a power cut | Battery at end of life | 29-NP712 battery, K94-37230 battery harness |
| Motor runs but the gate does not move | Gear reducer or drive chain | K32-36513-1 and K32-34656-1 reducers, K19-41043M chain |
| Gate overruns or stops short | APS encoder not counting | K76-34644 APS encoder, K1A6408 APE kit |
| Gate will not reset after an obstruction | Reset switch | K180A0357 reset switch |
| Cannot release the gate by hand | Cludge arm clamp or release handle | K75-50121 clamp and handle kit, K75-50120 release arm kit |
| Play or knocking at the output | Output shaft and sprocket worn | K77-36539 output shaft kit, K70-35678-1 sprocket kit |
| Operator dead, no board lights | Transformer or receptacle | APOW3 transformer, K76-37016 receptacle |
| No warning tone before the gate moves | Piezo alarm failed | K94-35152 piezo alarm |
Gate Operator Repair & Service Parts
| Ref | Part # | Description |
|---|---|---|
| 1 | K13-36117-1 | Cludge Cover |
| 2 | K75-50120 | Release Arm Kit |
| 3 | K09-50119 | Output Arm, Q059 |
| 4 | 75-50293 | Standard Arm Assembly, Q104 |
| 4 | K75-50292 | Swivel Arm Assembly, Q103 |
| 5 | 29-NP712 | Battery, 12V, 7AH |
| 6 | K1A6408 | APE Kit, 24V |
| 7 | K77-36541 | Antenna |
| 8 | K13-34729 | E-Box Cover |
| 9 | K1D8389-1CC | Main Board, DC Pad-Mounts, UL325 — RSW12U / RSW12UL |
| 9 | K1D8059-1CC | Control Board — RSW12VDC (pre-UL325) |
| 10 | APOW3 | Transformer |
| 11 | K76-37016 | Receptacle |
| 12 | K180A0357 | Reset Switch |
| 13 | K77-37335 | Electrical Box, RSW12U |
| 14 | K94-35152 | Piezo Alarm |
| 15 | K73-36109-1 | Chassis |
| 16 | K10-36395 | Battery Tray |
| 17 | K32-36513-1 | Gear Reducer, 30:1, Bottom |
| 18 | K77-37334 | Motor, 1/8 HP, 12 VDC |
| 19 | K19-41043M | Chain, #41 x 43 — no longer available |
| 20 | K32-34656-1 | Gear Reducer, 30:1, #60, Top |
| 21 | K75-36260 | Lock and Keys |
| 22 | K80-50295 | Access Door Keys, Qty 2 |
| 23 | K75-36294-1 | Cover — RSW12U / RSW12UL |
| 23 | K77-37856 | Cover, Grey — RSW12U / RSW12UL |
| 23 | K77-37332 | Operator Cover with Labels, Keys and Lock — RSW12VDC |
Parts Not Shown in Diagram
| Ref | Part # | Description |
|---|---|---|
| — | K94-37336 | Wiring Harness Kit, 12VDC |
| — | K94-37230 | Battery Harness, 7AH |
| — | K94-37236 | Battery Harness, 33AH, Solar |
| — | MPEL | Post-Mount Plate |
Service Kits
| Ref | Part # | Description |
|---|---|---|
| K1 | K75-50121 | Cludge Arm Clamp and Handle Kit, Q061 |
| K2 | K77-36539 | Output Shaft and Sprocket Kit |
| K3 | K76-34644 | APS Encoder, 24V |
| K4 | K77-37854 | Cover Kit — RSW12U |
| K4 | K77-39430 | Cover Kit — RSW12UL |
| K5 | K70-35678-1 | Sprocket Kit |