LiftMaster K74-39307-3 LA412UL Plastic Control Box — Enclosure Service Item

The LiftMaster K74-39307-3 is the plastic-control-box service reference listed by the manufacturer for LA412UL swing-gate equipment. It identifies the enclosure service item rather than a complete populated control system. Confirm the exact model, control generation and current box inventory before ordering; board, battery, solar supply and wiring references in an assembled operator drawing are separate selections. Select the replacement by the complete part number and the installed equipment configuration. A similar photograph or a shared LiftMaster brand name does not establish interchangeability. Confirm the applicable service drawing before ordering so the repair addresses the correct component and its related mounting, connection and operating requirements.

Compatibility — Models, Versions and Exclusions

Identify the Assembly and Plan the Repair

Inspect the enclosure, attachment points and cause of damage before choosing a box-only repair. Impact or water entry may affect internal equipment as well as the plastic housing. Have qualified gate personnel assess the board, battery connections and other installed components before deciding which parts can be retained in the replacement enclosure.

Confirm the current box, lid and mounting inventory against the exact operator generation. Do not infer that an assembled-system illustration supplies electronics, a battery or a solar panel with this enclosure reference. Restore approved wire routing, conductor entry protection and cabinet fit, then complete the required operator setup and entrapment-protection checks. No new enclosure rating is inferred from the word plastic.

Compare the replacement with the installed service arrangement before dismantling the equipment. Photograph the part’s location and record the complete model and visible service numbers. Inspect the surrounding attachment points and mating components for wear, impact damage or misalignment. Replacing one worn item will not correct a damaged support or another component that continues to impose abnormal loads on the repaired assembly.

Specifications and Product Identification

Before Ordering

• Record the complete equipment model, serial information and installed service reference.
• Verify the exact current K74-39307-3 recommendation.
• Separate package and contents.
• Different manufacturer enclosure references apply.
• Confirm the current supplied inventory and exact installation and final testing instructions.

Package Contents and Separate Requirements

This offer identifies the plastic-control-box enclosure service item. Confirm current lid, mounting and closure pieces. A main board, control-board bracket, reset switch, alarm, battery, solar panel, actuator arm and complete gate system are not established as included. Select separately damaged components from the exact LA412UL service information.

Safety Warnings — Read Before Installation or Service

• WARNING: A moving gate and exposed la412ul plastic control box — enclosure service item can cause serious injury. Installation and service require a qualified gate-systems technician.
• Isolate AC power, batteries and any solar supply as applicable, and secure the gate against unexpected movement before work begins.
• Keep people clear of the gate and drive during supervised testing. Never bypass required entrapment-protection devices or increase force to overcome a mechanical fault.
• Restore all covers and guards, then verify travel endpoints, reversal and every required safety device before returning the gate to normal operation.

Related Products and Important Differences

• LMRRUL monitored photo eye — a separate protection option only where the exact operator and control revision approve it; not a universal legacy retrofit.
• LMWEKITU monitored wireless edge kit — a separate edge communication system for approved controls and resistive edges; not a replacement for this mechanical or electrical service part.

Frequently Asked Questions

Is a control board included?

No board or populated electrical package is established as included with this enclosure reference.

Does it fit LA400UL automatically?

No. The manufacturer lists a separate LA400UL enclosure reference.

Is a solar panel supplied?

No panel or battery is established as included with this plastic box.

Can damaged internal parts be reused?

Qualified personnel must inspect the cause and extent of damage before deciding which components remain suitable.

Need Help Confirming the Right Product?

Contact Garage-DoorParts.com before ordering. Send the full equipment model, readable part labels and photographs of the installed assembly. Include the dimensions, electrical configuration or accessory details relevant to your project so the listing can be checked against the actual installation.