VEVOR Electric Trailer Jack, Power Tongue Jack Weight Capacity 3500 lbs, 9.84"-33.85" Electric Tongue Jack with Waterproof Cover for Lifting RV Trailer, Horse Trailer, Utility Trailer, Yacht Trailer

All products on our official website come with a 12-month warranty. If you purchase a product that has a problem within one year, we will be responsible for you. Here is the link: https://www.vevor.com/pages/return-policy. Yes, it has its own fuse.

Generally, a seven-pin plug is used, and only two wires are used. It depends on your actual needs. This is a single-wire version, so there is only one positive wire.

Yes. I had 2 of them and neither would work. Either the switch or motors were bad. I am getting another brand.

Yes

You need to unplug the 7-pin connector on the jack to connect the trailer lights. This connector is not shared by all wiring.

Yes, it can be used.