LiftMaster K75-12566 Limit Switch Kit for MGJ / MJG Commercial Operators
The LiftMaster K75-12566 limit switch kit services the electrical limit switch portion of select LiftMaster MGJ / MJG commercial operator limit systems. Limit switches are part of the travel-control system that tells the operator when to stop at the open and close positions. When a switch is damaged, unreliable, or no longer actuated correctly, the operator may stop at the wrong point, fail to stop consistently, or require professional limit-system troubleshooting.
This listing should be kept separate from the K72-12565 limit shaft assembly. The switch kit addresses the switch portion of the system, while the shaft kit addresses the mechanical shaft, sprocket, bearings, and limit nuts. On older commercial operators, both the switch and mechanical parts should be inspected because replacing only one part may not correct the symptom if the other side is worn.
Supplier references describe K75-12566 as a replacement limit switch kit for LiftMaster standard line electro-mechanical commercial door operators and MGJ / MJG applications. Because some references list this item as no longer available, verify current availability and confirm the exact parts diagram before building the repair around this part.
Compatible With / Common Applications
- Select LiftMaster MGJ / MJG commercial door operator applications where the parts diagram lists K75-12566
- LiftMaster standard line electro-mechanical commercial door operators requiring this specific limit switch kit
- Commercial operator repairs where the limit switch portion, not the limit shaft assembly, is the failed part
- Related MGJ electrical box and limit-system service paths when the diagram confirms this switch kit
- Not a substitute for K72-12565 limit shaft kit or other switch kits used on J, H, HJ, GH, T, GT, SD, GSD, or Logic-series operators unless confirmed by diagram
Features & Specifications
| Feature / Specification | Details |
|---|
| Manufacturer | LiftMaster |
| Product Type | Limit switch kit |
| Part Number | K75-12566 |
| Application | MGJ / MJG commercial operator limit switch service |
| Compatible Operator Type | Select standard line electro-mechanical commercial operators |
| System Area | Travel limit / open-close limit switch system |
| Notes | Some supplier references list limited or no availability; verify current stock and exact diagram callout |
Also Known As / Related Part Numbers
- K75-12566
- 75-12566
- LIF-K75-12566
- LiftMaster MGJ limit switch kit
- LiftMaster MJG limit switch kit
- Limit Switch Kit MGJ
- Limit Switch Kit MJG
Technician Note
If the operator limits drift or do not repeat, check the mechanical limit shaft and limit nuts as well as the switch kit. A failed switch and a worn shaft assembly can create similar symptoms.
Before Ordering
- Confirm the diagram calls for K75-12566
- Inspect the existing switch and shaft assembly before ordering
- Check for loose actuators, worn limit nuts, or damaged wiring
- Verify current availability before promising a repair date
- Have a qualified technician reset and test limits after replacement
Professional Advisory
Commercial door operator electrical parts should be installed and tested by a qualified commercial door technician. Disconnect power before service, follow the operator wiring diagram, and do not bypass required safety devices, interlocks, or monitored entrapment protection.
Product Questions & Answers
What does K75-12566 replace?
It replaces the limit switch kit on select LiftMaster MGJ / MJG and standard line commercial operator applications.
Is this the same as the K72-12565 limit shaft kit?
No. K75-12566 is the switch kit. K72-12565 is the mechanical limit shaft assembly kit.
Can a bad limit switch cause overtravel?
Yes, but overtravel can also be caused by worn mechanical limit parts, incorrect adjustment, wiring issues, or door/operator problems.
Is this part still available?
Some supplier references list limited or no availability, so current inventory should be checked before upload or sale.
Should limits be tested after installation?
Yes. A technician should set and test the open and close limits and confirm safe operator function after replacement.
