It might just be a bad float or pump. Also may just be gunked up. Take a wet - dry vac and get the water out and take it apart and clean it up. You can use white vinegar n a small brush. It may be ok. After you get it all straight, poor some pine sol, a cup or so, (we use the tropical scent) down the shower drain and in the a/c pan few times a season. It will keep the gunk at bay and also leave a pleasant scent. You should exercise all of your bilge pumps at least a couple times per year to make sure they are working properly.
