GTO FM144 Automatic Gate Lock
The GTO FM144 Automatic Gate Lock is an automatic electric lock accessory used to help secure a swing gate after the gate opener closes. Instead of relying only on the operator arm to hold the gate shut, the lock catches into a receiver so the gate is less likely to move from wind pressure, animal contact, gate flex, or light forced movement. It is commonly used on driveway gates, farm gates, animal enclosures, longer gate leaves, and dual swing gates where the closed position needs extra stability.
This lock is often searched under both GTO FM144 and Mighty Mule FM143. The part is commonly used across GTO, Mighty Mule, and Linear Pro swing gate operator families, but the wiring method depends on the opener control board. Some systems connect directly to lock terminals, while older or different boards may require the included lock control board or a specific wiring diagram. Do not guess at control-board wiring. Match the opener manual, model number, and terminals before connecting the lock.
Mechanical alignment is just as important as electrical compatibility. The gate must swing freely, close firmly against a positive stop, and bring the lock body and receiver into alignment every time. If the gate sags, drags, flexes, or does not close to the same spot, the lock may hang up, chatter, or fail to latch even if the lock and opener are working. For dual gates, the correct leaf must open first and close last so the latch and receiver meet in the right sequence.
Compatible With
Select single and dual Mighty Mule, GTO/PRO, GTO, Linear Pro Access, and related swing gate opener systems; commonly associated with Mighty Mule FM143 and GTO FM144 gate lock applications; many Mighty Mule and GTO swing opener families including FM500, FM502, FM350, FM352, MM371W, MM372W, MM571W, MM572W, MM271, MM260, MM360, GTO PRO 2000XL, 2002XL, 3000XL, 3200XL, 4000XL, 4200XL, 3000XLS, 3200XLS, 4000XLS, and 4200XLS systems when supported by the control board and wiring diagram. Verify the opener manual and wiring terminals before installation.
Features & Specifications
| Manufacturer | GTO / Mighty Mule / Linear |
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| Product Type | Automatic electric gate lock |
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| Part Number | FM144 |
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| Application | Swing gate lock accessory for automatic gate opener systems |
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| Compatible Operator Type | Select single and dual GTO, Mighty Mule, and Linear Pro swing gate openers |
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| Voltage | Low-voltage accessory powered through compatible opener control wiring |
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| Included Components | Lock with low-voltage wire, lock receiver, clevis pin, locking cap, lock control board, battery lead wires, terminals, wire connector, cable ties, keys, and lock decal when supplied as a complete kit |
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| Mounting Hardware | Gate-specific mounting hardware is typically not included and must match the gate material |
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| Gate Requirements | Gate must close firmly against a positive stop and the lock receiver must align with the latch |
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| Notes | Commonly referenced as GTO FM144 and Mighty Mule FM143; LOCKPCB is a related replacement lock control board |
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Also Known As / Related Part Numbers
FM144, FM143, GTO FM144, Mighty Mule FM143, Automatic Gate Lock, Electric Gate Lock, GTO Automatic Gate Lock, Mighty Mule Automatic Gate Lock, Linear Pro Access gate lock, LOCKPCB, lock control board, lock PCB, FM143/FM144 lock kit.
Technician Note
Before replacing a lock that will not latch, check gate alignment, closed limit, stop position, receiver placement, and dual-gate sequencing. Many lock problems are caused by the gate not returning to the same closed position rather than a failed lock coil or control board.
Before Ordering Checklist
- Confirm the gate opener is a compatible swing gate operator.
- Verify whether the system is single or dual gate.
- Check that the gate closes against a positive stop.
- Confirm the lock and receiver can be mounted level and aligned.
- Review the opener manual for lock terminals or lock board wiring.
- Select proper mounting hardware for tube, chain link, wood, or metal gate construction.
Professional Advisory
Disconnect power before working inside an operator control box. Do not bypass obstruction sensing or safety devices to make a lock latch. If wiring, force settings, sequencing, or gate movement are uncertain, have a qualified gate technician inspect the system.
Product Questions
Is FM144 the same lock as Mighty Mule FM143?
FM144 and FM143 are commonly associated automatic gate lock part numbers used across GTO, Mighty Mule, and Linear branded swing gate systems. Match the kit contents and opener manual before ordering.
Does this gate lock work on single and dual swing gates?
Yes, it is commonly used on select single and dual swing gate opener systems. Dual gates require proper leaf sequencing and positive stops for reliable lock operation.
Why does the gate need a positive stop?
The lock latch has to meet the receiver in the same place every time. A positive stop helps the gate close firmly and keeps the lock from hanging up or missing the receiver.
Is mounting hardware included?
Gate-specific mounting hardware is typically not included because tube gates, chain link gates, wood gates, and metal frames use different bolts, brackets, or U-bolts.
What causes an automatic gate lock not to latch?
Common causes include poor receiver alignment, a gate that drags or binds, an incorrect closed limit, missing positive stop, wrong gate sequencing on dual gates, or a latch that needs light silicone lubrication.
