Liftmaster Q166, Q055, Q165 Replacement Limit Switch Kit Swing Gate Openers

Liftmaster Q166, Q055, Q165 Replacement Limit Switch Kit Swing Gate Openers

The LiftMaster K75-50189 is a replacement limit switch kit used on select LiftMaster and Elite swing gate operator systems. The limit switch assembly is a key part of the operator travel system. It tells the control system where the gate should stop in the open and close directions, helping prevent overtravel, hard stops, and repeated limit adjustment problems.

This kit is commonly searched under the older Elite references Q166, Q055, and Q165. Those numbers are tied to limit switch hardware used on swing gate perimeter access operators, including CSW-type and Robo Swing style applications. Because LiftMaster and Elite operators have gone through multiple generations, the safest way to confirm fitment is to match the original part number, switch layout, mounting style, and parts diagram for the exact operator.

Compatible With

Common Compatible Models and Families

• Select LiftMaster and Elite swing gate perimeter access systems using K75-50189 limit switch hardware
• CSW and CSW200 style commercial swing gate operators when shown in the operator parts diagram
• Robo Swing / RSW style swing gate operators associated with the Q165 limit switch assembly
• Older Elite swing gate operators using Q055, Q165, or Q166 limit switch references

Important Compatibility Notes

• Do not choose this kit only by the gate operator brand. Verify the original limit switch assembly and parts diagram.
• Some CSW, RSW, and Robo Swing operators use different limit hardware depending on age and configuration.
• This is a limit switch kit, not a main control board, motor, or complete mechanical arm kit.

Features & Specifications

Also Known As / Related Part Numbers

• K75-50189
• LM-K75-50189
• Q166
• Q055
• Q165
• LiftMaster Q166 limit switch assembly
• LiftMaster Q055 limit switch holder
• LiftMaster Q165 limit switch assembly Robo Swing
• Elite Q166
• Elite Q055
• Elite Q165

Technician Note

A bad or damaged limit switch assembly can cause the gate to stop in the wrong place, fail to learn travel correctly, or continue driving after the expected stop point. Also inspect cams, wiring, mounting hardware, and the physical gate stops so a new switch kit is not blamed for a separate mechanical problem.

Before Ordering

• Match K75-50189, Q166, Q055, or Q165 to the old part or parts diagram.
• Confirm the operator is a compatible swing gate model, not a slide gate operator using different limit hardware.
• Check for broken limit cams, damaged wiring, loose hardware, or water intrusion around the switch area.
• Confirm the switch mounting style and connector/wire layout before replacing the part.
• After installation, set and test open and close limits according to the operator manual.

Professional Advisory

Limit switch replacement involves moving gate hardware and electrical controls. Disconnect power before service and have a qualified gate technician handle the repair if the gate is moving unpredictably, the operator has high-voltage wiring exposed, or the limits cannot be safely tested.

Product Questions & Answers

What does the K75-50189 limit switch kit do?

It helps the swing gate operator identify the open and close stop positions so the gate does not overtravel or stop in the wrong place.

Is K75-50189 the same as Q166, Q055, or Q165?

K75-50189 is commonly cross-referenced with Q166, Q055, and Q165 limit switch assembly references. Match the old part and operator diagram before treating them as interchangeable.

What operators commonly use this limit switch kit?

It is commonly associated with select LiftMaster and Elite swing gate perimeter access systems, including CSW-style and Robo Swing style applications when confirmed by parts diagram.

Can a bad limit switch cause the gate to run too far?

Yes. A failed switch, loose switch mount, damaged cam, or wiring issue can cause incorrect open or close stopping points.

Should this be installed by a technician?

A qualified gate technician is recommended if the operator has unsafe gate movement, exposed wiring, or repeated limit failures after adjustment.