If it is a submersible pump, normally the contacts at the caravan wall is the problem, a clean with a nail emery board, Steal it from your wife or partner, and try again. Over 15 years I have replaced one Truma pump and now use a whale pump on the Truma connector to my Coachman at least every trip I have to " Wiggle " the connector to make the electrical connection.
Always carry a spare pump and hose unit.