Liftmaster LA400 LA400DC LA400U LA400UL Parts

LiftMaster LA400 linear actuator swing gate operator replacement parts diagram

LiftMaster LA400, LA400DC, LA400U & LA400UL Replacement Parts

Genuine LiftMaster replacement parts for the LA400 family of linear actuator swing gate operators — the 24 VDC battery-backed arm operators that drive the gate with a sealed electric ram. The diagram and tables below cover the original LA400 control box and the arm parts. Control-box parts for the LA400U and LA400UL, and the LA400DC replacement arms, are in the product list further down this page.

Which LA400 do you have? Open the control box and read the part number on the board. The control boxes share almost nothing between generations, so match the board before you order.

Model	Control board	Arm
LA400	K001A6039, metal box	Arm parts in the table below
LA400U / LA400UL	K1D8388-1CC, UL325 board in a plastic box	Arm parts in the table below
LA400DC	Read the number on your board and match it in the product list below	LA400DC primary, LA400DCS secondary

Two assemblies, two tables. The control box parts (Refs 1–8) are in the wall-mounted box; the operator arm parts (K1–K4) are on the actuator itself.

Careful with the bracket kits. K77-19130 is the standard hardware kit; K77-19130-1 is the two-post variant. One digit apart, not interchangeable.

The fuse is not a LiftMaster part. It is a standard 20 amp automotive blade fuse. The K74-30941 kit is there if you would rather buy it with the correct spares.

Common LA400 Repairs

Symptom	Usual cause	Parts to check
Gate runs on mains but dies in a power cut	Battery pack at end of life	K74-30762 battery pack, K74-30754 battery harness
Operator completely dead	Blown fuse or transformer	K74-30941 fuse kit, K74-30763 transformer
No response to remotes, wired controls work	Receiver module or antenna	K001A5747 receiver module, K74-19499 antenna
Gate will not reset after an obstruction	Reset switch	K23-19380 reset switch
Arm hums but the gate does not move	Motor or drive nut worn	041ASWG-0438SA motor, 041ASWG-0442SA release lever
Cannot release the gate by hand	Release lever or key	041ASWG-0442SA lever, 041ASWG-0119 release keys
Intermittent operation, arm cuts out	Cable between box and arm	041ASWG-0489 24V cable with connector
Erratic behaviour after a board swap	Firmware chip version	K-127A0071E chip V1.6

Original LA400 Control Box

Ref	Part #	Description
1	K001A6039	Control Board, LA400
2	K75-15480	Control Box and Cover, LA400
3	K75-30764	Control Board Mounting Bracket
4	K23-19380	Reset Switch
5	K74-19499	Antenna
6	K74-30762	Battery Pack, 12V, 7A
7	K74-30763	Transformer
8	K76-19446	Alarm
—	K74-30941	Fuse Kit
—	K001A5747-2	Receiver Module, 315MHz
—	041ASWG-0119	Release Key, Qty 2
—	K001A5747	Receiver Module, 315MHz
—	K-127A0071E	Chip, V1.6, LA400
—	K74-30754	Battery Harness
—	K77-19130-1	Two Post Bracket Kit, LA400 / LA412

Gate Operator Arm

Ref	Part #	Description
K1	041ASWG-0442SA	Release Lever
K2	041ASWG-0438SA	Motor, 24V
K3	041ASWG-0014SA	Rear Connector
K4	041ASWG-0489	Cable, 24V, 3m, with Connector
—	K77-19130	Hardware Kit, LA400 / LA412