First thing to do is check your battery condition. This problem can be caused by an old or weak or poorly charged battery, or by dirty or loose connections at the battery, or by low water in the battery. If that's all ok, you probably have a weak circuit breaker.
You're looking near the battery for a row of 12V DC mini-circuit breakers, covered by a red rubber boot. If you trace the heavy wire from the battery to the row of breakers, you'll see a copper buss bar connecting the breakers. On the other side of the breakers, wires go to the various powered devices. Two of those wires are thicker than the others, as shown in the attached photo. If you closely inspect the 2 breakers for those wires, one will have a teeeeeeenny, tiny reset button. The other breaker is for the hydraulics. You'll want to replace that one.
