Hi DonHelenL,
There's a buss bar near the battery with automotive style 12V circuit breakers. The high current devices like the hydraulics pump are powered through one of the circuit breakers. As mentioned, it's usually a 50amp auto-reset breaker. If the pump draws more than 50 amps, the breaker trips and a few seconds later automatically resets.
In cold weather the viscosity of the hydraulic fluid in the pump can cause the pump to draw extra amps. A bind in the mechanism can also cause this. Loose connections are another possibility. Also, if the battery voltage is a bit low, the amperage goes up. And as mentioned, sometimes the breaker gets weak.
If it persists, a new 50 amp breaker will usually fix the problem. At one time Lippert had a service bulletin recommending replacing it with an 80 amp breaker, but I think they may have withdrawn that bulletin.
50 amp auto-reset 12V circuit breakers can often be found at auto parts stores or marine stores, or at RV dealer parts departments. They usually run $10 or less. Check the orientation of the mounts to get one that matches yours.