Doubt that it’s low on fluid. Fluid goes out to extend the jacks and to extend the slides. Retracting them brings the fluid back to the reservoir. Never fill the reservoir with jacks down or slides out. Big mess when you retract. Guess if there is a sensor on the reservoir it could look for a low fluid situation but it just doesn’t sound practical as there’d be no room for error. If the tank was a little low, the alarm would always sound. If it was a little over full, the alarm would never sound.
I think there are sensors on each jack to show when it’s fully retracted. Don’t know if you could visually determine if one is not retracted as much as the others or not. I did take a block of wood one time and hammered mine up. Slapped all four and apparently one wasn’t quite seated as the alarm stopped.
2006 Gulf Stream Friendship G7
350 Cat, Crusier Lift w/ Honda VTX
Blue Ox and 2019 Chevy Blazer RS AWD V6