1. Overview

An electric gas strut, also called an electric linear actuator, can be used to lift and close the service window of a food trailer. The system is simple: AC power enters a power supply/transformer, the transformer outputs DC power, and a forward-reverse switch changes the DC polarity to make the strut extend or retract.
The supplied wiring drawing shows five terminals on the transformer side: L, N, ground, V+ and V-. The DC output V+ and V- are connected to a forward-reverse switch, and the switch output is connected to the electric strut terminals V+ and V-.

2. Main Components

Component	Function
Power supply / transformer	Converts the trailer AC input into DC power for the electric strut. Connect the AC input to L, N and PE/ground. Connect the DC output to V+ and V-.
Forward-reverse switch	A DPDT reversing switch changes the polarity sent to the actuator. One direction extends the strut and opens the window. The other direction retracts the strut and closes the window.
Electric strut / actuator	The motorized support installed between the trailer body and the service window panel. Its two wires connect to the switch output.
Mounting brackets and bolts	Mechanical fixing points must be strong enough to support the window weight and the push/pull force of the actuator.

3. Wiring Procedure

1. Disconnect power before wiring. Make sure the trailer is not connected to mains power. Do not work on live wiring.
2. Connect AC input to the transformer. Connect the live wire to L, the neutral wire to N, and the protective earth/ground wire to the ground terminal. The ground connection is required for safety.
3. Connect DC output to the reversing switch. Connect the transformer output V+ and V- to the input side of the forward-reverse switch as shown in the wiring diagram.
4. Connect the switch output to the electric strut. Connect the output side of the switch to the V+ and V- wires of the electric strut. When the switch is pressed one way, the strut extends. When pressed the other way, the polarity reverses and the strut retracts.
5. Test the direction. Briefly power the system and press the switch. If the window moves in the opposite direction from the switch label, turn off the power and swap the two actuator output wires.
6. Secure and protect all wiring. Use insulated terminals, cable clips, and protective conduit. Keep wires away from sharp metal edges, hot cooking equipment, water areas, and moving hinges.

4. Connecting Two Electric Struts on One Window

For wide food trailer windows, two electric struts may be installed on the left and right sides. In that case, the two actuators are normally connected in parallel to the same switch output, so both receive the same polarity at the same time. Use two matched actuators with the same voltage, stroke length, speed, and load rating. The power supply must also provide enough current for both actuators working together.
If the two sides do not move evenly, stop testing immediately and check the mounting angle, friction, actuator specifications, and electrical connections. Do not force the window to move, because uneven movement can twist the service window frame.

5. Installation and Safety Notes

• Choose the correct transformer voltage for the actuator, such as 12 V DC or 24 V DC, according to the actual label on the actuator.
• Use a fuse or breaker on the supply side according to the actuator current rating and local electrical requirements.
• Install the switch where the operator can see the window moving while pressing the control.
• Do not place the switch or exposed terminals near water splashing areas unless a suitable waterproof enclosure is used.
• After installation, open and close the service window several times and check for abnormal noise, loose bolts, heating wires, or unstable movement.
• Final electrical connection should be checked by a qualified electrician, especially for export trailers that must meet local electrical standards.

6. Quick Troubleshooting

Problem	Possible Check
The strut does not move.	Check AC input power, transformer output voltage, fuse, switch terminals, and actuator wiring.
The strut moves in the wrong direction.	Turn off power and swap the two actuator output wires on the switch output side.
The strut moves but stops under load.	The window may be too heavy, the mounting angle may be wrong, or the transformer current may be insufficient.
Two struts move unevenly.	Confirm both struts have the same specifications and that both brackets are aligned symmetrically.

Conclusion

The connection method for a food trailer window electric gas strut is: AC live, neutral, and ground into the transformer; transformer V+ and V- into the forward-reverse switch; and switch output V+ and V- to the electric strut. The switch reverses polarity so the actuator can extend to open the window and retract to close it. Correct wiring, secure mechanical mounting, and proper safety protection are all necessary for reliable daily food trailer operation.

Important: This article is a practical wiring overview based on the supplied diagram and photos. Always match the actual component labels and voltage ratings before wiring.