I can only open or close my travel trailer Hi-Lo using AC power ,it doesnt respond when I,m using the 12 volts,battery is in good condition also I checked the fuses which is good? Any sugetstion ,Thank you for your answer.

Welcome to the forum. Check the postion of your three way rocker switch. Do you hear anything when you try to raise or lower while on battery? make sure that the battery is fully charged.

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"Ruben"
2404T, 2003 2500HD 4X4 GMC Sierra SLT Crew Cab w/Astro camper shell and 2003 Chevy Tahoe LE 4X2
Far West Texas

What year is your trailer? Normally, the problem is just the opposite. The top DOES NOT raise on AC power - period! The motor that lifts it is a 12V DC motor that receives its power directly from the battery.

Unless some former owner rewired and rebuilt it somehow, it should not work on AC power.

- Jack

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Hi-Lo 1707T - Tire Minder TPMS on Tow Vehicle and Trailer, 300W Solar Battery Charger, Equal-i-zer WDH, Progressive Dynamics Converter, Fan-Tastic Fan, LiFePO4 battery 12V DC Electrical System, SoftStartRV mounted on A/C
2024 F150 Platinum FX4 3.5L PowerBoost SCrew

It works when connect to the ac power,but if I disconnect from ac power it doesn't,I'm not saying it receives AC power ,just connect to park AC power.

I agree! Something has been modified to be able to do that. Some photos of the pump would help to solve the mystery.

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My Great Wife Joyce
2018 Jayco Jay Flight 21QB
Formerly owned 1705T and 2310H
2012 F150 4X4 SuperCrew EcoBoost w/Leer Cap
Reese WD Strait-Line Hitch
Amateur Radio K3EXU

When you are not connected to an AC source, do other DC devices, such as interior lights, work when the 3 way switch is in the proper position? If not, it could be that the DC breaker from the battery has been tripped. The breaker is usually located in, or on the outside of the battery/pump case mounted on the tongue, and has small reset button on the side.

My understanding is that the AC to DC transformer directly powers DC devices, as well as charges the battery for when there is no AC.