Recently, a neighbor at my storage lot had to replace his electric tongue jack because water had intruded the gears and the jack was Froze-up. Shortly after he had his problem the cap on my electric jack cracked and I had to replace it.
These incidents had me looking for a weather proof cover of some type that could protect my electric jack and it's inner workings.
I finally found a cheap, easy solution. I am using a tire cover. The material is weatherproof and I simply use a bungee cord to secure it onto my tongue. The elastic at the top makes a nice pocket that covers the top of the jack and the rest of the tire cover drapes down to protect my coupler, my electrical connector and my chains.
This will work to protect your jack even if you have a manual jack.
Happy Scamping !!!