Liftmaster SW420 Hall Effect Sensor Kit Operators
The K74-18381 hall effect sensor kit is a service part for the feedback system in select LiftMaster swing gate operators. In practical terms, this type of sensor helps the control board monitor operator movement and motor rotation so the gate can run through its travel properly. A failed or damaged sensor can look like a control-board problem, a limit issue, or a motor issue, so the surrounding wiring and mechanical condition should be checked before replacing parts. The most supportable compatibility for this kit is the LiftMaster SW420GL swing gate operator. Similar-looking hall effect kits used on slide gate operators or other swing models may have different harnesses, mounting points, or board connections. This is why the parts diagram and original sensor number matter more than appearance alone.
Compatible With
- LiftMaster SW420GL swing gate operators
- LiftMaster SW420 swing gate operator family when confirmed by parts diagram
- Applications using original sensor numbers SN75G0552 or G75G0552
- Not a universal replacement for K74-G0589, K74-18379, or other hall effect sensor kits used on different operator families
Features and Specifications
| Manufacturer | LiftMaster |
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| Product Type | Hall effect sensor kit |
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| Part Number | K74-18381 |
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| Application | Movement/motor feedback sensor replacement |
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| Compatible Operator Type | Select LiftMaster SW420GL swing gate operators |
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| Included Components | Hall effect sensor kit components as supplied by manufacturer |
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| Notes | Verify connector, harness routing, and parts diagram before ordering |
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Also Known As / Related Part Numbers
- K74-18381
- SN75G0552
- G75G0552
- 75G0552
- LiftMaster SW420 hall effect sensor kit
Technician Note
A hall effect fault should not be diagnosed by appearance alone. Inspect the magnet/target area, damaged wires, pinched harnesses, corrosion, and control-board inputs before replacing the sensor.
Before Ordering Checklist
- Confirm the operator model is SW420GL or a supported SW420 variant.
- Compare the original sensor part number to K74-18381, SN75G0552, or G75G0552.
- Inspect the harness and connector before ordering.
- Check for mechanical binding that may cause sensor-related faults.
- Disconnect power before servicing the operator.
Professional Advisory
Gate operator troubleshooting may involve moving gates, pinch points, and electrical components. A qualified gate technician should handle diagnosis when the operator moves unpredictably or when high-voltage wiring is exposed.
Product Questions and Answers
What operator is the K74-18381 hall effect sensor kit used with?
K74-18381 is commonly listed for the LiftMaster SW420GL swing gate operator and should be verified against the SW420 parts diagram before ordering.
What does a hall effect sensor do on a gate operator?
The sensor helps the control system read motor or movement feedback so the operator can monitor travel and operation correctly.
Is K74-18381 the same as SN75G0552 or G75G0552?
SN75G0552 and G75G0552 are commonly listed as related or also-known-as numbers for the K74-18381 hall effect sensor kit.
Can this sensor be used on slide gate operators?
Do not assume this SW420 sensor kit fits slide gate operators. LiftMaster uses similar hall effect parts on other models, but the part number and connector must match.
What should be checked before replacing this sensor?
Check the operator model, harness condition, connector style, magnet or target area, and any diagnostic codes before replacing the sensor.
